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Wright Aircraft Engines 

Complete Instructions for their Installation, 
Operation and Maintenance 



Edited by 

JOHN R. CAUTLEY 

Sales Manager 




PUBLISHED BY 

WRIGHT AERONAUTICAL CORPORATION 

Paterson, New Jersey, U. S. A. 

1921 



. I j f * 



COPYRIGHT, 1921 

BY 

THE WRIGHT AERONAUTICAL CORPORATION 



By Transfer 

Ir Corps 

OCT 2 2 1930" 



PRINTED AND BOUND 

BY 

THE ESSEX PRESS, NEWARK, N. J. 



-ZX-IO?^ 



CONTENTS 



SECTION I. Description of Engines 

pages 

Description of Models E-2, H-2 and H-3 - 1 to 9 

Description Model A - 10 to 14 

Description Models E and I . 15 to 18 

Description Model H 18 

Description of Carburetors Used 20 to 27 

Starters — Bijur and Hand — Fuel and Oil 27 and 28 

SECTION II. Installation and Operation 

Suggestions for Design of Installations — Radiation 31 to 33 

Unpacking Engines 34 

Installing in Fuselage. 35 to 37 

Starting Engine 38 and 39 

SECTION III. Overhaul and Repair Instructions 

Engine Disassembly - 42 to 47 

Cleaning Engine Parts 48 

Overhaul of Engine 49 to 65 

Timing Wright Engines 66 to 70 

Wiring Diagrams 71 and 72 

Carburetor Overhaul 73 and 74 

Tabulated Data of Wright Engines 76 and 77 

Tool Lists 78 



in 



The Price of this 
Volume is $5.00 



PREFACE 



T 



HIS book has been produced with the intention of providing the most 
complete possible instructions for operating" and overhauling Wright 
aeronautical engines. 



It is intended primarily for the use of those who have in their charge a 
number of such engines, but it covers the whole field. The airplane designer 
will find in it all the information he requires to enable him to provide the 
best installation. The pilot will find detailed instructions for handling the 
engine and a catalogue of the simple troubles. For hangar men there are 
hints for the daily care of those parts which should receive it. 

Perhaps the greatest pains have been taken with that section devoted to 
the overhaul of the engine and its accessories. The methods described are 
all the result of the aggregate experience of men who have worked in field 
and base repair shops. Thev are methods adapted to the needs of such 
shops and frequently differ from factory methods, in that they call for a 
minimum of special tools and fixtures. 

Particular emphasis is given to some instructions on points which may 
appear to the reader to be of small importance ; however, great care has been 
taken not to stress anything unduly. Where small matters are made very 
prominent it is because field experience with thousands of engines has shown 
the necessity for special care. 

The section of the book dealing with overhaul is written for the actual 
mechanic who does the work, as well as for his superintendent. It is 
assumed that he will be fully acquainted with the grade of workmanship 
necessary for aviation engine repair, for which reason there is no reference 
to elementary matters of craftsmanship. 

For use when ordering spare parts the Wright Aeronautical Corporation 
publishes a parts list separate from this volume, which is an instruction 
book only. 

For assistance, or for explanation of points found not to be fully covered 
in this book, application should be made to the company's Service 
Department. 

WRIGHT AERONAUTICAL CORPORATION, 
Paterson, N. J., U. S. A. 



WRIGHT AERONAUTICAL ENGINES 



MODEL E-2 WRIGHT ENGINE 
AVERAGE PERFORMANCE AT SEA LEVEL 



R. P. M. 
1600 
1800 
2000 





Lbs. Fuel 


Lbs. Fuel 


Lbs. Oil 


H. P. 


Per H. P. Hour 


Per Hour 


Per Hour 


176 


.485 


86. 


3.6 


200 


.48 


96. 


4. 


220 


.487 


107. 


4.4 



Recommended speed 1800-2000 R. P. M. Weight dry 480 lbs. 
2.18 lbs. per Horse Power at 2000 R. P. M. 



ALTITUDE PERFORMANCE MODEL E WRIGHT ENGINE AT 1800 R. P. M. 

Sea 

Altitude Level 

Horse Power 200 

Altitude Performance Charts for Model E-2 have not been made, but the E-2 will give 
greater power than Model E given above. 



5000' 


10,000' 


15,000' 


20,000' 


25,000' 


30,000' 


166 


138 


113 


91 


75 


63 



MODEL H-3 WRIGHT ENGINE 
AVERAGE PERFORMANCE AT SEA LEVEL 



R. P. M. 
1800 
2000 





Lbs. Fuel 


Lbs. Fuel 


Lbs. Oil 


H. P. 


Per H. P. Hour 


Per Hour 


Per Hour 


325 


.48 


156. 


6.5 


360 


.5 


178. 


7.2 



Recommended speed 1800-2000 R. P. M. Weight dry 617 lbs. 
1.71 lbs. per horse power at 2000 R. P. M. 



ALTITUDE PERFORMANCE MODEL H-3 WRIGHT ENGINE AT 1800 R. P. M. 

Altitude Level 5000' 10,000' 15,000' 20,000' 25,000' 30,000 

Horse Power ... 325 272 224 184 148 120 102 



"SUPER FIGHTER" WRIGHT ENGINE 
MODEL H-2 OR H-3 USING 6V 2 :1 COMPRESSION 50' ( GAS, 50' , BENZOL 

SEA LEVEL PERFORMANCE 

Lbs. Fuel 
R. P. M. H. P. Per H. P. Hour 

1800 360 .48 

2000 390 .44 

Recommended speed 1800-2000 R. P. M. Weight dry 617 lbs. 
1.58 lbs. per Horse Power at 2000 R. P. M. 

For guaranteed Horse Powers see Page 76. 



SECTION I. 

Description of Engines 



WRIGHT AIRCRAFT ENGINES 

General Description, Giving Particulars of and 
Reasons for the Main Features of Their Design 



AT the present time — August, 1921 — there are being 

AA produced, 2 different models of Wright engines. 

-*- -*■ These are closely similar in design and differ 

mainly in size, being rated at 180 H. P. for Model E-2, 

which is the smaller, and at 300 H. P. for Model H-3. 

The general description of the 
motors and also the maintenance 
and overhaul instructions in the 
several sections of this volume, 
deal primarily with these two 
models. In the description 
which follows no dimensional 
data are given. This is all com- 
bined in a single table of specifi- 
cations covering all the different 
models, which is printed on 
page 76. 

Seven Models 

Five other models have been 
built in America, first model A, 
then an improved type which 
was called model I, then model 
E, which is almost identical with 
model I except that it has higher 
compression and gives more 
power, model H, which was the 
first 300 H. P. Wright Engine, 
and H-2. 

Large numbers of these en- 



gines are in use and in general 
respects they differ so little from 
the present production, models 
E-2 and H-3, that what applies 
to one applies to the whole seven 
models. 

However, where differences 
exist these are dealt with fully 
in supplements which will be 
found at the end of this section 
of the book. Where instructions 
given do not apply to all seven 
engines this fact is noted and 
reference to the proper page and 
section is made. 

Unique Features 

There are two basic features 
peculiar to all Wright motors. 



DIFFERENCES BETWEEN 
VARIOUS MODELS 

Models E-2 and H-3 

Fully described pages 1 to 9. De- 
scription holds good generally for 
all models except as tabulated be- 
low and described fully pages 10 
to 19. 

Have heavy head sleeves, with in- 
creased cooling, minimizing valve 
trouble. 

Model A 

Connecting rod design peculiar to 

model A. 

Piston design peculiar to model A. 

Magneto drive peculiar to model A. 

Propeller hub attachment peculiar to 

model A. 

Valve guide design peculiar to 

model A. 

Models E and I 

These are identical except that 
model E has a longer piston giving 
higher compression than model I. 
Magneto drive and mounting pecu- 
liar to models E, I and H. 
Piston design peculiar to these two 
models. 

Oiling system peculiar to these two 
models. 

Model H 

Larger than models E and I but gen- 
erally similar except: 
Oil pump design same as for H-2. 
Piston same as for H-2. 
Magneto has hand advance control. 

Model H-2 

Does not have adjustable vertical 
shaft. 



the cylinder construction and the valve operation. 
The cylinders are separate steel sleeves flanged at the 
bottom for attachment to the crank-case and with flat 
steel heads in which the valve seatings are cut. These 
sleeves are threaded for almost their entire length and are 

screwed into an aluminum water 
jacket which carries the valves 
and the camshaft. The resulting 
effect of this construction is to 
provide an aluminum cylinder 
block completely lined with steel. 
All stresses within the cylin- 
der are transferred directly to 
the crankshaft and crankcase 
through the steel sleeves, the 
aluminum having only to carry 
the camshaft, and this means 
that the cylinder block is very 
strong, while being very light in 
weight. The cylinder block is 
enameled inside and out, protect- 
ing the aluminum from corrosion 
due to impurities in the cooling 
water or in the atmosphere. 

The valve seats are cut in the 
steel heads of the cylinder sleeves 
and the valve stems project up- 
wards through cast iron guides 
screwed into bosses in the alum- 
inum. A flat tappet of mush- 
room form is attached directly to 
the upper end of each valve stem 
and the detail of the tappet ad- 
justment is one of the most in- 
genious features of the motor. 
The valve stems are of large 
diameter and are hollow, being 
threaded internally ; the tappet 
has a flat head with a notched 
edge and its underside is ser- 
rated, the top surface, on which 
the cam bears, being case-hard- 
ened. The stem of the tappet 
screws deeply into the hollow 
valve stem. 



Easy Tappet Adjustment 

Beneath each tappet there is 
a washer with tine serrations 



2 



WRIGHT AERONAUTICAL ENGINES 



^ 




MODEL H-2 
WRIGHT ENGINE 





These views show the Model H-2 Wright Engine 
with complete standard equipment, as sent out from 
the Wright plant. H-3 identical externally except for 
modified water connections. 



V^: 



-SJ 



WRIGHT AERONAUTICAL ENGINES 




Explanatory diagram of valve tappet adjustment 

which mesh with those on the underside of the tappet. 
The hole in the center of the washer is not circular but 
is made to fit slots cut on the top end of the valve stem, 
and around the periphery of this washer are a number of 
small holes. The valve springs [of which there are two 
for each valve, one inside the other] come immediately 
beneath the washer and hold it up against the tappet. 

Xow. owing to the washer fitting into the slots on 
the A'alve stem, it cannot turn on the valve and, if the 
washer is held, the tappet can be turned, the serrations 
between the two "clicking" over each other and yet hav- 
ing grip enough to lock the tappet securely, since they 
are subjected to the full pressure of the valve springs. A 
special wrench is used for this adjustment which can be 
performed with great ease and quickness. 

The camshaft is mounted in three bronze bearings 
bolted to the top of the cylinder block, so that the cams 
act directly upon the tappets without any intermediate 
mechanism. Camshaft and valves are inclosed by an 
oiltight aluminum cover and operate in a perfectly lubri- 
cated condition. 

Camshaft Drive 

At the end of each cylinder block there is a vertical 
shaft which drives the camshaft through bevel gearing. 
This is called "the upper vertical shaft" and has a dis- 
connecting joint above the level of the crankcase so that 
it forms a unit with the cylinder assembly: Thus cylin- 
ders, valves, camshaft and camshaft-drive form a com- 
plete unit which is both light and compact. 

Crankcase Construction 

Owing to t)ie nature of the cylinder assemblies the 
crankcase is comparatively simple. There are upper and 
lower halves split on the center line of the crankshaft, 
and the respective parts of the bearings are carried 
directly in the crankcase halves. The upper and lower 
crankcase halves are bolted together very strongly and, 
since each half takes its share in supporting the crank- 
shaft, the case as a whole is very rigid and light in 
weight. Both halves are aluminum castings and the 
upper half has a projecting foot running the entire length 
of the case on each side forming the bedplate from which 
the engine is supported. 

In the upper half, at the rear end, there are two short 
shafts in bronze carriers called the lower vertical shafts. 



Each of these shafts has a bevel gear at the lower inside 
end meshing with a bevel gear on the crankshaft. The 
upper ends of these two shafts project above the crank- 
case and are slotted to receive the tongues on the ends 
of the upper vertical shafts which are attached to the 
cylinder blocks as described. It is thus possible to re- 
move and replace cylinders without disturbing any of the 
camshaft drive gearing. 

On five of the models of Wright engines timing 
the camshafts is a somewhat complicated operation and 
is dealt with fully on pages 66 to 70. In Model E-2 
and H-3 it is rendered extremely simple by means of a 
serrated jaw coupling integral with each of the upper ver- 
tical shafts. 

Timing Model E-2 and H-3 

The upper bevel pinion which meshes with the cam- 
shaft gear sets in a bronze bearing pushed into the 
cylinder block casting. Through this bearing passes a 
short hollow shaft integral with the pinion. The lower 
end of this hollow shaft projects about three-quarters of 
an inch below the bearing and is splined. On these 
splines is forced a disk with fine radial serrations. 

On the vertical driveshaft there is splined a corre- 
sponding disk and the shaft itself continues on upward, 
passing right through the hollow shaft of the bevel 
pinion and terminating in a thread on which there is a 
nut. By tightening this nut the driveshaft is lifted until 
the two serrated disks are locked together. In order to 
time the camshaft the nut is loosened and the shaft 
gently tapped downwards till the teeth on the disks come 
out of mesh. In this position the camshaft can be 
rotated freely and when set correctly it only remains to 
lighten the nut once more. (See cut page 67.) 

A factor which increases the accuracy of this adjust- 
ment is that the vertical shaft runs at one and a fifth 
crankshaft speed, thereby giving a two and two-fifths to 
one reduction between vertical shaft and camshaft which 
means that for each degree of camshaft rotation there is 
a 2 deg. : 24 min. movement of the vertical shaft. This 
permits the serrations to be quite substantial and yet 




Cylinder assembly complete and ready tor 
attachment to crankcase 



WRIGHT AERONAUTICAL ENGINES 



allow a delicacy of adjustment within two degrees of 
accuracy. 

It may be remarked that while this adjustment is not 
employed on the older models of Wright motors it is 
capable of being applied thereto since all the parts inter- 
change with those of the older designs. 

Pump Drive 

The lower half of the crankcase supports another 
shaft with a bevel pinion at its upper end, this pinion 
meshing with the same gear on the crankshaft which 
drives the upper vertical shafts. This shaft is also verti- 
cal and is mounted in a bronze carrier socketing into a 
hole in the aluminum of the case. The lower end of this 
shaft has a tongue through which the drive for the oil 
and water pumps is taken, in a manner to be described 
later. In order to minimize weight all the intermediate 
shafts run at a speed one-fifth greater than that of the 
crankshaft. The increase of speed also enables the size, 
and therefore the weight, of the oil and water pumps to 
be kept very low. 

The crankshaft is hollow throughout, for lightness and 
for the passage of oil. It is supported on four babbitt 
faced bronze bearings and one ball bearing, the latter 
being at the rear end immediately in front of the bevel 
gear. The front end of the crankshaft has a taper on 
which the propeller hub is mounted and directly back of 
this is a ball thrust bearing housed in the crankcase. 

Magneto Drive Models E-2, H-2 and H-3 

The rear end of the crankshaft is splined to receive 
the master bevel pinion which drives all the supple- 
mentary shafts. Immediately behind this short splined 
portion and across the extreme end of the shaft there is 
a deep slot, into which fits a corresponding tongue on the 
magneto drive shaft. 

There are two magnetos, each eight-cylinder instru- 
ments. One is wired to all the spark plugs located on 
the outer sides of the cylinders, the other to all the plugs 
situated in the Vee, between the blocks. The magnetos 
are mounted crosswise with their distributor ends tilted 
upward and towards the outside of the engine, at an 
angle of 35 degrees to the horizontal, which in most 
installations makes the breaker boxes very accessible. 

It should be observed that tilting the magnetos also 
has the advantage that it permits the engine bearers of 
the fuselage to be continued straight backward as far 
as the constructor of the airplane may desire ; since no 
part of the motor interferes therewith. 

Both magnetos, with their drive shaft and gears are 
made up in a unit and are demountable as such. The rear 
end of the crankcase has a circular, flanged opening pro- 
vided with a ring of studs, and the aluminum magneto 
bracket attaches thereto. There are three magneto gears : 
central in the bracket is a short shaft with a tongue at 
the front end which fits into the slot in the end of the 
crankshaft and at the other end, housed in the bracket, 
is a ball bearing which supports the shaft. A bevel pinion 




Inner and outer connecting rods 

on this shaft meshes with two others, one on each side, 
these being also mounted on ball bearings. 

The magnetos themselves are attached to the bracket 
by cap screws and a very simple and effective form of 
coupling is used. On the end of the armature shaft is a 
small spur gear with 23 teeth and on the bevel pinion 
shaft is a similar gear but with 24 teeth. To connect the 
armature and pinion shafts there is a sleeve furnished 
at both ends with an internal gear which just fits the 
little spur gears. When this sleeve is located symmet- 
rically both the internally toothed portions mesh with 
the spur gears and so give a solid drive connection which 
has ample freedom to allow for such small inaccuracies 
of alignment as may exist. A spring is used to maintain 
the sleeve in its driving position, but by removing a 
cotter pin the sleeve is freed, can be slid back out of 
mesh, and the magneto can then be timed with great 
accuracy ; since by moving forward one of the 23 teeth 
and simultaneously moving backward one of the 24 teeth 
the effect is obtained of an advance of seven-tenths of 
one degree. 

A magneto can, of course, be removed without affect- 
ing the coupling, since the gear simply slides out when 
the cap screws holding the magneto to the bracket are 
removed. If a hand starting crank is used, it is attached 
directly to the back of the magneto bracket, the shaft 
being prolonged and the end of the bracket flanged for 
this purpose. In cases where a gasoline pump is em- 
ployed, this also is attached to the bottom of the magneto 
bracket, taking its drive from a short vertical shaft and 



WRIGHT AERONAUTICAL ENGINES 



another bevel gear meshing with the main magneto driv- 
ing gear. It should be noted that the magnetos are 
absolutely identical since, owing to the bevel gear drive, 
they both rotate in the same direction. 

Pistons of Models E-2, H-2 and H-3 

The pistons are of aluminum alloy and are of quite 
simple design. There is no ribbing beneath the heads of 
E-2, H-2 and H-3 as the section of the head is heavy 
enough both for strength and. what is more important, to 
carry away the heat from the center of the head rapidly. 

Each piston carries four compression rings and one 
scraper ring near the bottom of the skirt. Here occurs one 
of the small differences between the E-2 and the H-3 
engines, the H-3 having four ring grooves, one for each 
ring, and the E-2 having the rings in pairs in two grooves 
of double width. Wrist pin bearing surface is about 
equally divided between the small end of the connecting 
rod and the bosses of the piston, the pin being free to 
turn in either. On model H-2, to prevent endwise move- 
ment of the pin, there is an aluminum cap at each end, 
the cap itself being held against turning by tongues which 
fit in slots cut in the piston. 

In the case of model E-2 and H-3 a bronze button is 
forced into either end of the wrist pin which leaves the 
pin perfectly free to float or turn as it likes while the 
presence of the bronze removes any possibility of scratch- 
ing the wall of the cylinder. 

Connecting Rods 

There are, of course, two connecting rods operating 
on each crankpin and these are of different form. They 
are known as outer and inner rods respectively. The 
inner rod has a hollow, tubular shank which is split 
toward the lower end and opens out into two flat feet 
which attach to a bronze "box" by four bolts. These 
same four bolts hold together the two halves of the 
bronze box, which is split in two halves and babbitt lined, 
so forming a conventional lower connecting rod end of 
the marine type. 

The outside of the bronze, in the space between the 
two feet of the forked rod, is turned and forms the 
bearing for the outer connecting rod lower end, this be- 
ing split in the normal way and held together by two 
bolts. This design allows for the fitting of a new set of 
bearings with ordinary tools and methods ; also the 
bronze being a very good conductor helps to dissipate 



E-2 — Inclined bracket has boss on bottom for 
attaching Wright geared fuel pump. A hand 
starter or Bijur starter can be attached in addition 
to fuel pump. 

H-2 and H-3 — Inclined bracket has pad for at- 
taching Sylphon fuel pump at back. There is no 
provision in this bracket for attaching Wright 
geared fuel pump or starters. 




/ 





Diagram of gear train for one cylinder block 

the heat produced by the friction. Model A has rods of 
an entirely different design described on page 11. 

Lubrication System Models E-2 and H-3 

There is one main oil channel, this being a steel tube 
cast in the lower half of the crankcase, in which the oil 
pump is located as already described. From this main 
channel oil passes to the four main bearings of the 
crankshaft. Each of the main bearing bushings is com- 
pletely encircled by a groove cut in the aluminum which 
is thus kept full of oil. Passing through holes in the 




Rear view of inclined magneto bracket 



WRIGHT AERONAUTICAL ENGINES 



(r 



^ 



DIFFERENT TYPES OF PISTONS USED 
IN VARIOUS MODELS 



^ 





Original Model A design 




7 ype of ring 

grooves on 

A. I, E, E-2 



Piston pin retainer 

ring on early 

E and I 



Type of ring \ 



grooves on 
H-2 and H-3 



Piston pin plug 

on later E, I 
and H and H2 



E-2 Piston 



H-3 piston has plug type pis- 
ton pin retainers similar to E-2 ; 
but is otherwise the same as 
H-2 piston. 




^: 



WRIGHT AERONAUTICAL ENGINES 





Model E-2 oil and water pump assembly 



bushing oil reaches the crankshaft, and passing on 
through holes in the shaft completely fills the inside 
thereof, passing out again through other holes which 
lead to the lower ends of the connecting rods. Further 
holes in the inner connecting rod member lead oil to the 
outer rod bearing. Piston and wrist pin lubrication is 
performed by the oil spray exuding from all bearings. 

Camshaft and valve lubrication is obtained by taking 
oil from the groove around the front end main bearing 
and leading it up through two small steel pipes, one at- 
tached to each cylinder block. These lead to holes in the 
aluminum registering with holes in the front end cam- 
shaft bearings. Thence the oil enters the camshaft itself, 
which is hollow from end to end, small holes drilled in 
each cam allowing lubricant to be discharged directly 
upon the tappets. These holes are on the opening face 
of the cam and so oil the tappet head just as the cam 
begins to lift. The excess not only lubricates the valves 
themselves but flows into the bearings supporting the 
upper vertical shaft. Here it obtains access to the space 
inside the tube inclosing the vertical shaft, falls clown 
this, lubricates the lower vertical shaft bearings and re- 
turns to the crankcase. Every bearing and gear is thus 
taken care of in proportion to its requirements. 

Thrust Bearing Oiling 

For lubrication of the main thrust bearing on the 
front end of the crankshaft the methods used on models 
E-2 and H-2 differ slightly. In the former there is a 
lead drilled in the crankcase which connects the main 



channel to the thrust bearing, 
the hole being small enough to 
prevent so great a flow of oil 
as to cause a drop in pressure. 
On Model H-2 the bearing is 
not connected with the pressure 
line, but directly above it is a 
pipe which attaches through a 
rubber hose to the vent of the 
external oil tank. 

On Models A, E, I, H and 
H-3 the thrust bearing is taken 
care of by the general spray 
from other bearing. 

When the front end of the 
engine is at a lower level than 
the rear end, as when diving or 
climbing according as to whether 
the ship is a tractor type or not, 
there is a tendency for oil to 
collect in the front end of the 
valve cover. Here, if too great 
an accumulation occurs, valve 
fouling may result. To guard 
against this on Model E-2 a small 
pipe is taken out of the valve 
chamber at the front end and 
run back to the crankcase. This 

overflow line is made up alongside the pressure line from 

crankcase to camshaft. 

Oil Pump System Models H, E-2, H-2 and H-3 

There are in all three oil pumps of which one is the 
feed pump and two are the suction pumps. The feed 
pump draws its oil from an external tank and forces it 
through a screen into the main feed line. The two suction 
pumps take oil from the two ends of the crankcase and 
deliver it to the external tank, an oil radiator usually be- 
ing placed between the pumps and the tank although 
tank and radiator are sometimes combined in a single 
unit. 

The object of this triple pump system is to keep the 
crankcase dry at all times. If the engine is steeply in- 
clined so that all the oil escaping from the bearings runs 
to one end of the crankcase, then one alone of the suction 
pumps will operate ; the other, as it will be drawing air 
instead of oil, merely idles until such time as the plane 
changes its inclination. 

All three pumps are made in a single unit, mounted 




E2H 



Old type oil pump with shaft and vanes 
half withdrawn 



8 



WRIGHT AERONAUTICAL ENGINES 



on a base plate. In the bottom of the crankcase there is 
a large orifice into which the pump assembly fits, being 
held in place by a number of studs and located exactly 
by a pair of dowels. There is a single casting forming 
the body for all three pumps and a single spur gear drives 
all three. This gear is situated centrally and its shaft has 
a slot in the upper end which engages with the tongue 
on the lower end of the pump drive, mentioned on page 
4, the dowels in the crankcase and base plate ensuring 
alignment. The base plate is perfectly flat on its upper 
surface to which the pump body is attached, but it is a 
cored casting containing all the intake and outlet oil 
passages for the three pumps. 

Running in various directions in a horizontal plane, 
these cored passages lead to a number of holes in the 
surface of the base plate, which holes correspond with 
similar holes in the crankcase, in turn leading to the vari- 
ous lines which comprise : 

Main pressure line. 

Suction line from the front end of the crankcase. 

Common external outlet from both suction pumps 

which is piped to the radiator. 
External suction for the pressure pump which is 

piped to the tank. 

The intake for the suction pump which cares for the 
rear end of the crankcase has no line of course, but is 
merely an opening in the pump body covered with a 
coarse screen for the purpose of excluding particles of 
solid matter which might be in the oil and be large enough 
to injure the pump gears. 

Thus except for the two external connections to 
radiator and tank, all the oil lead junctions are made 
automatically when putting the pump assembly in place. 

There is a difference between the E-2 and H-3 in that 
the former has the suction line to the front end of the 
crankcase cast inside the case, while the latter has an 
external line. Also there is a difference in the form of 
the oil screen, this being cylindrical in the case of E-2 
and removable from the side of the crankcase, while on 
H-2 it is hemispherical and is removed from beneath. 
There are also some detail differences in the pump con- 
struction, but the principle remains the same. In both 
motors there is an oil pressure relief valve situated on 
the side of the crankcase and communicating with the 
filter screen chamber, on the delivery side of the screen. 





Parts of air pressure pump 

It may be remarked that the whole of the oil system as 
just described is different from that used on earlier 
models, the lubrication of which is dealt with in the 
supplements on old models, pages 11 to 18. 

Water System All Models 

The water pump is a simple centrifugal type with two 
outlets. It is placed directly beneath the oil pump and 
is attached to the underside of the oil pump base plate, 
thus forming an integral part of the oil pump assembly. 
The main oil pump driveshaft extends right through the 
casing and has a square hole in its lower end into which 
a squared end of the water pump shaft fits. A rather 
unusual and effective detail is that the gland nut on the 
water pump is recessed so as to catch any oil that may 
escape down the drive shaft and conduct it to the pack- 
ing. The two water pump outlets connect by separate 
pipes to the outer, rear corners of the cylinder jackets, 
and the hot water issues from the upper, front corners 
to the radiator.* E-2 and H-3 engines are built with 
copper water pipes attached from pump to cylinder in- 
takes. 

Carburetion 

A Stromberg carburetor has been used since the early 
Summer of 1918. It is described in detail on pages 20 to 
24. There are two intake flanges on each cylinder block 
connected together by cast aluminum pipes and these lie 
close against the blocks. Above the carburetor there is a 
water jacketed aluminum casting having two outlets on 
the sides and two underneath. To the latter the two 
outlets on the duplex carburetor connect, the side outlets 
attaching to the center of each intake branch. On one 
side the connection is by a flange bolting solidly in place, 
and on the other side there is a short intermediate piece 
provided with a gland, allowing for expansion. This 
layout with the double form of carburetor is equivalent 
to two separate carburetors and intake systems, one for 
each block. 

Air Pump 

Since gasoline is fed to the carburetor by air pressure 
in many installations, the left hand valve cover carries a 
small air pump which comprises a bronze cylinder and 



Body, rotor, and packing nut of water pump 



* This applies to a tractor installation, the connections 
are, of course, reversed for a pusher. 



WRIGHT AERONAUTICAL ENGINES 



a piston with a cup leather. The piston is driven from 
the rearmost exhaust cam, its suction stroke being given 
by a spring that is compressed on the working stroke of 
the pump. The pump is not adjustable and supplies air 
at a higher degree of compression than is ever likely to 
be required. Various regulating devices for controlling 
the. pressure in the fuel tank are in use but these are not 
part of the engine. 

Accessory Drive 

The rear end of each valve cover is provided with a 
threaded boss and each camshaft has a screwdriver slot 
in the rear end. In all installations a tachometer or 
motor speed indicator is used and the flexible shaft for 
driving this instrument is attached to a special connec- 
tion supplied with the engine. This consists of a short 
brass body, screwing in the boss on the valve cover and 
containing a short shaft meshing with the camshaft slot 
and arranged at the outer end to take the standard form 
of flexible shaft connection. The tachometer can be 
attached to either camshaft, the hole in the end of the 
other valve cover being plugged. 

Camshaft turns half the speed of crankshaft in oppo- 
site direction so tachometer must be geared 2 to 1 to read 
correct engine speed. 

Propeller Hub 

The propeller hub fits on the taper at the front end of 
the crankshaft and is not an interchangeable part in the 
ordinary sense of the word. Each hub is lapped by 
hand till it is a perfect fit on the taper and the key only 
performs part of the function of taking the drive, since 
the hub is drawn very tightly on the shaft. If the hub 
is not a perfect fit too much stress comes on the key and 
the hub is liable to "work" on the shaft. This will tear 
the shaft and hub and perhaps make it impossible ever to 
remove the hub. 

The hub is locked in place by two nuts, of which one 
screws on the end of the crankshaft and the other into 
the nose of the hub itself. These two nuts fit one within 
the other and are free to turn relatively. That threaded 
into the hub has a finer thread than the one threaded on 
the shaft. In putting on the propeller the hub is drawn 




up by the inner nut, the outer being left a few threads 
unscrewed. When the inner nut is completely tightened 
it is locked by pulling up the outer nut and the two are 
then double locked by a clip wire. The purpose of the 
use of two threads of different pitches is seen when the 
propeller is to be removed, for then, after taking off the 
wire clip, both inner and outer nuts are undone simul- 
taneously. The differential action of the two threads then 
gives great pulling power, which is necessary to break 
the hub free of the taper. Model A has a different form, 
described page 33. 



D 



lmensional 



Data 



It may have been observed that in this description no 
dimensional details have been given. All such will be 
found on pages 76 to 77 under the heading "Tabulated 
Data." This covers all models of Wright engines and 
enables ready comparison to be made. 

Fuel Pump Model E-2 

On model E-2 provisions have been made for attach- 
ing a Fuel Pump. This is attached directly to the bottom 
of the magneto bracket, taking its drive from a short ver- 
tical shaft and another bevel gear meshing with the mag- 
neto driving gear. 

Air Pressure Relief Valve 

The Air Pressure Relief Valve is not supplied with 
motor equipment, but due to its positive operation, we 
recommend same to be used in connection with all models 
using air pressure for the fuel system. The valve as 




Tachometer drive connector 



Air pressure relief valve 

shown in cut consists of a leather plunger diaphram with 
the air under pressure on one side of the diaphram being 
balanced by a spring on the other side of diaphram. The 
spring is adjusted by small plug to desired pressure and 
locked by nut to prevent variation. 

The valve can be assembled any way with reference to 
inlet and outlet lines. When excessive pressure is 
reached, the spring releases and allows air to pass out oi 
line by means of several relict holes just beneath air 
pocket. The leather diaphram seats tightly maintaining 
pressure without leaks. 



10 



WRIGHT AERONAUTICAL ENGINES 



rr 



=^\ 



MODEL A WRIGHT ENGINE 




Showing the piston and connecting rod construction peculiar to model A 
Also the double intake on the water pump 



:^ 



MODEL A— SPECIAL POINTS IN DESIGN 

Model A Was the Original Wright, Almost 
Identical With French Hispano-Suiza Motor 



T 



HE most conspicuous differences between the de- 
sign of Model A and all the other models is the 
connecting rod construction. 



As for all models these rods have hollow, round sec- 
tion shanks, but the lower end design is entirely different. 
Instead of the bronze box attaching" to the forked end 
of the inner rod, it is the outer rod that is forked. There 
is thus a divided cap on the lower end of the outer rod, 
with a space between. After fitting this cap it is ground 
internally, just like the single end of the outer rod in the 
other designs. 

Model A inner rod is forged with a lower end of very 
much the conventional gasoline engine type, but this 
lower end is not only bored but is turned on the outside 
also. It is split, and the cap attached by one pair of 
centrally located bolts. The bore of the inner rod is 
made larger than the crankpin and the outside is smaller 
than the internal diameter of the outer rod ends. This 
Laves quite a thin section of metal in the lower end of rod 
and cap, and this is drilled all over with small holes for 
babbitting. 

By means of special tool equipment this lower end is 
then covered with babbitt both inside and out ; the inside 
is fitted to the crankpin, the outside to the outer rod 
lower end. It should be particularly observed that this 
babbitting can only be performed successfully with com- 
plete factory equipment of an elaborate nature. The 
model A rod construction is slightly lighter than the 
marine type used on all the other models, but it is less 
durable, owing to the extreme difficulty of making a 
sound job of the babbitting, to the impossibility of refitting 
a bearing with ordinary tools, and to the fact that the 
thinner sections cause the bearing to run hotter. 

Pistons 

Model A pistons have thinner heads and a number of 
internal ribs or webs to support the heads. The wrist 
pin is fixed in the piston by a lock screw which threads 
into one of the piston bosses and passes right through 
the wrist pin. 

Magneto Mounting 

Instead of being a separate assembly altogether, the 
magnetos on Model A are attached to platforms located 
behind each cylinder block and cast integrally with the 
crankcase. 

On the upper end of each of the lower vertical shafts 
there is a bevel pinion, and a corresponding pinion is 
attached directly to each magneto armature shaft. When 
the magneto is bolted down on its platform the pinions 



mesh; the drive being thus direct without any joint giving 
universal motion, wherefore the location of the magnetos 
has to be very accurate. 

For timing, the pinion attached to the magneto arma- 
ture has a flange mating with a similar flange on the part 
which is keyed to the shaft. Three bolts in slotted holes 
secure the two flanges together, thus allowing for adjust- 
ment. 

Lubrication System 

The original Model A was designed to operate with- 
out an oil radiator or external tank, the whole supply 
being carried in the crankcase, automobile fashion. This, 
however, caused considerable trouble from overheated 
oil and radiators where usually fitted. 




Model A connecting rod 



12 



W RIGHT AERONAUTICAL ENGINES 



fr 



: ^\ 



MODEL E-2 WRIGHT ENGINE 




Showing the inclined magneto position and also the oil strainers 
and pressure release valve 



. -1 






■ 



MODEL E-2 WRIGHT 
ENGINE 




Points clearly shown in this section ate the timing device on the upper vertical shaft, the magneto drive and the way in which bo 
pressure and suction oil lines are arranged internally. Also the separate oil feed to the thrust bearing 
and thick cylinder sleeve heads 






; 















■"■-' 



MODEL E and I 
WRIGHT ENGINE 




This cut shows Model E. Model I 
has a shorter piston, giving lower com- 
pression, but there is no other difference. 



WRIGHT AERONAUTICAL ENGINES 



13 



The general circulation outward from the feed side 
of the pressure pump is the same for all models with the 
difference that model A has : 

1. No feed to the thrust bearing on the crank- 
shaft. 

2. No drain pipes from the front end of the valve 
chambers. 

Model A has only a single oil pump, which circulates 
oil in one of two ways : 

1. From the crankcase sump, through the system 
and back to the sump. 

2. From a radiator and small tank placed directly 
beneath the engine, through the system, back to the 
crankcase, and thence by gravity down into the 
radiator, etc. 



The oil pump itself is located in the same position as 
for other models, connecting for drive with the short 
bevel driven vertical shaft by means of the same sort 
of tongue and slot. It is not a gear pump, however, but 
is what is known as a vane type and operates as follows : 
The pump body is cast iron and is cylindrical inside and 
outside. It fits into a bored chamber in the crankcase, the 
bottom of the body being flanged and secured by studs. 

The pump shaft passes right through the body but 
slightly eccentric to its bore. Through the shaft is a 
slot, and in this slot fit two bronze vanes or paddles, held 
apart by small coil springs, which force the vanes out 
against the walls of the pump body. Owing to the eccen- 
tricity the vanes slide through the slot in the shaft as the 
latter revolves. In the body, on the side furthest from 
the shaft, are holes connected to the suction line, while 
directly opposite are the pressure outlets. The vanes in 




Model A Engine, showing magneto 
mounting peculiar to this model 



14 



WRIGHT AERONAUTICAL ENGINES 



sweeping over the walls "wipe" the oil from the suction 
side and compress it into the delivery side. Very high 
pressures can be pumped provided the vanes are fitted 
accurately. 

On the pressure side of the pump there is a cylindrical 
screen contained in a cavity in the crankcase, and remov- 
able from beneath. There is a pressure relief valve 
similar to that used for the other engines and located on 
the side of the crankcase. 

The lower half of the crankcase is much deeper in 
the center than at the ends and a suction line is cast in 
the case, ending at the bottom of the sump, where there 
is a large plug. When using an oil radiator this plug is 
removed and is replaced by a hollow 
outlet connected by a short hose to the 
radiator. The suction line inside the 
case is closed by a brass plug and suc- 
tion connection is made by a line taken 
from a normally plugged hole in the 
rear end of the crankcase. 

Timing Camshafts 

The serrated coupling on the upper 
vertical shaft, which is used for cam- 
shaft timing on model E-2 and H-3, is 
absent from all the older models. On 
A, E, I, H and H-2 the vertical shaft is 
one continuous piece of steel from the 
driving tongue at the lower end to the 
bevel pinion at the top. Accuracy in 
timing is then obtained by the use of 
three adjustments, either singly or in 
combination. 

Firstly, the camshaft can be changed 
relative to the vertical shaft, one tooth 
at a time, as in all gear combinations. 

Secondly, owing to the camshaft gear 
having two and two-fifths times the 
number of teeth on the vertical 
shaft pinion, by lifting the verti- 
cal shaft out of mesh with the 
lower vertical shaft and giving it 
one-half turn the 
equivalent of 
about one- 
half tooth 
variatio n 
can be ob- 
tained. 



Thirdly, the camshaft gear, which has 36 teeth, has 
one key way only cut in it, but the shaft end has five 
keyways. Thus by removing the gear and changing the 
placing of the key in the shaft we shift the gear relative 
to the shaft 72 deg. But there being 36 teeth in the gear 
each tooth covers 10 deg. Thus shifting the key back 72 
deg. and then going seven teeth forward in the meshing 
gives the effect of a two degree retardation. 

The propeller nut is attached by a single nut on which 
are two different threads on this nut, a coarser internal 
thread and a finer external ; consequently the nut screws 
onto the shaft faster than into hub. This gives the differ- 
ential action necessary to force the hub on the taper tightly. 




Section of Model A Wright Engine arranged for 
use without an oil radiator 




MODELS E AND I-SPECIAL POINTS IN DESIGN 



These Models Marked the First Large Departure From 
French Designs, Having the Marine Type Connecting Rods 



T 



dE difference between models E and I is very 
slight indeed. By using a different proportion of 
piston the compression on model E is higher than 
on model I and the former is intended to run at a higher 
speed, thereby developing more power from the same 
piston displacement. This affects certain details of the 
magneto timing, etc.. which are covered in the Table of 
Specifications and in the instructions for adjustment and 
overhaul. The description of the points in design which 
follows applies to both models E and I. Except for the 
points covered herein the design is the same as that of 
models E-2 and H-3 dealt with in pages 1 to 10. 

Pistons 

These are without ribs under the head, the head being 
thick enough both for strength and the rapid conduction 
of heat away from the center. The wrist pins float, being 
free to turn in either the small end of the connecting rod 
or in the piston bosses. On early E and I engines, to pre- 
vent the ends of the pin from scoring the cylinder walls 
there is a special, thin section piston ring in a groove 
which passes diametrically across the piston bosses. The 
later model E engines have had the wrist pins retained by 
aluminum caps like the piston of model H-2. 

There are four compression rings placed in pairs in 




two grooves and a scraper ring, as well as the ring which 
secures the wrist pin, the latter not being thick enough to 
touch the cylinder wall. 

Magneto Mounting 

At the rear end of the crankcase a bracket is attached 
which carries the magnetos in much the same way as on 
models E-2 and H-2. However, instead of the magnetos 
being tilted upward, they set with their bases horizontal, 
on a level a little above that of the crankshaft center. 

There is a centrally located driveshaft connecting with 
the crankshaft precisely as for models E-2 and H-3, but 
instead of carrying a bevel pinion it has a spiral gear 
upon it. With this gear there meshes a companion pinion 
on a cross shaft mounted in ball bearings in the bracket, 
and to the outside ends of this shaft are attached the 
magneto couplings of the identical design of models E-2 
and H-3. Since both magnetos are thus driven off 
opposite ends of a common shaft they rotate in opposite 
directions, which means that one right hand and one left 
hand magneto is necessary instead of two right hand 
instruments. 

Lubrication System 

The primary motion magneto driveshaft is carried 
out through the back of the magneto 
bracket somewhat as in models E-2 
and H-3, but instead of being used for 
the application of a starting device, it 
operates small gear type pump. 

The pressure pump is exactly like 
that of model A (see cuts pages 7, 



Model E 
Wright 
Engine 



Showing location ot oil strainer on Model E engine 



WRIGHT AERONAUTICAL ENGINES 



17 



S\ 



MODEL E-2 
WRIGHT ENGINE 





These views show the Model E-2 Wright Engine 
with the complete standard equipment, as sent out 
from the Wright plant. 



V^: 



=^ 



18 



WRIGHT AERONAUTICAL ENGINES 



REAR 




«P| Above — Body shaft and vanes of oil pump used on Models A, E and I. 
Left — Oil pump assembly of Model H. 



FRONT 



14 and 18), but with the difference that there is no suc- 
tion line inside the crankcase. The lower half of the case 
is deepest at the center, and oil escaping from the bear- 
ings runs out through a hose connection plug in the middle 



of the sump. Thence it passes to the suction side 
of the little gear pump driven off the end of the 
magneto drive-shaft, which in turn delivers it 
through the oil radiator to a main tank. It is 
from this latter that the pressure pump draws its 
supply. 

This layout gives the same dry sump effect that is 
obtained with models E-2 and H-2, but the pump arrange- 
ment is much less compact and more external piping is 
required. 



MODEL H— SPECIAL POINTS IN DESIGN 

This Model Was Designed With Many Differences From the 
French 300 HP. Engine, Notably the Triple Oil Pump System 



THE design of model H is in all general respects 
similar to that of models E and I, having only one 
really important point of difference, this being the 
lubrication system. 

This is the same as for models E-2 and H-3 (see 
description, page 7) except that the detail design of the 
triple oil pump is different. The pump fits into the 
crankcase as a complete assembly in just the same way 
and the circulation is exactly the same. 

Instead of having an internal suction line for with- 
drawing oil from the front end of the crankcase there is 



a pipe attached externally underneath the crankcase. 
Also there is no separate feed for the thrust bearing 
on the crankshaft, this being lubricated by the same 
spray which cares for pistons and wrist pins. With 
these reservations the description, page 7, applies 
throughout. 

The model H pistons are unlike the early models E 
and I in that the method for retaining the floating wrist 
pin consists of aluminum caps instead of an additional 
piston ring. Model H piston is exactly like that of 
model H-2 (described page 5). 



WRIGHT AERONAUTICAL ENGINES 



19 



rr 



: ^ 



-Tapping fit in Shaft 
/Loose Fit 




~ 



m 





END VIEW OF MAGNETO 
ADVANCE 



Magneto mounting details of Model H Wright engine 
(See page 37) 



V^: 



CARBURETORS OF WRIGHT ENGINES 

Describing the Principle of Action of the Stromberg Used on 
Present Models and the Zenith Used on the Original Model A 



ON the original model A Wright engine the car- 
buretor was a Zenith D.C.48. On models E, I 
and E-2 it is a Stromberg NA-D4. On models 
H, H-2 and H-3 it is a Stromberg NA-D6. The principle 
of the two Stromberg instruments is identical, in fact they 
are almost identical in all respects except size. 

A slight change in the size and number of the holes in 
the accelerating well has been made for the H-3 and the 
carburetor called NA-D6A. 

In the following pages the principle and design of, 
first the Stromberg and then the Zenith carburetors, is 
described. For instructions regarding the overhaul of 
carburetors see page 71. 

Stromberg Principle 

A prominent feature of Stromberg carburetors is the 
use of two venturi, a small one within a larger one. The 
main gasoline discharge nozzle stands vertically in the 
center of the small venturi and the two venturi are con- 
centric, the upper edge of the small one standing just a 



trifle higher than the smallest diameter of the large one. 
Air entering the large venturi thus has an ejector action 
on the small one, accelerating the velocity of the air 
passing through the latter ; the object being to subject 
the main discharge nozzle to high velocity air which is 
most effective in atomizing the gasoline. 

Thus the small venturi discharges a highly atomized 
spray of air and fuel at high velocity, into the body of 
air coming through the large venturi at a lower speed. 
This gives a two-stage mixing of the gasoline with the 
air ; resulting in a more even mixture than would be 
obtained from a single venturi. Also the two-stage 
system, by ensuring a high velocity around the discharge 
nozzle at comparatively low engine speeds, enables a 
good, combustible mixture to be produced at partial 
throttle openings. 

Idling 

From the main gasoline supply channel between the 
float chamber and the main discharge nozzle a small 
tube is carried vertically upward to a fine, vertical slot 



THROTTLE STOP 
SET SCREW X 

THROTTLE LEVER 



LARGE VENTURI 
TUBE PILOT SCREW 



IDLE ADJUSTMENT 
NEEDLE 



MIXTURE CONTROL 
LEVER 




ACCELERATION SCREW 
PLUG 



GASOLINE 
CONNECTION 

FLOAT LEVER 
FULCRUM SCREW 

Z DRAIN PLUG 



GAS CHAMBER PLUG 



AIR HORN DRAIN 
COUPLING 



Stromberg Aviation Engine Carburetor used on Wright Engines 



WRIGHT AERONAUTICAL ENGINES 



21 



cut in the carburetor body in such a position that the 
edge of the throttle disk lies against the slot when closed. 
Immediately behind this slot is a small adjustable orifice 
communicating with the atmosphere. Thus, when the 
throttle is closed there is suction through the portion of 
the slot exposed on the engine side of the throttle disk. 
This suction draws gasoline up the vertical pipe ; and air 
through the orifice. As the throttle is opened through 
its first few degrees of movement it uncovers more and 
more of the slot, thereby increasing the supply of mix- 
ture to the engine. 

Owing' to the air orifice being very small the amount 
of gasoline drawn in increases, as the throttle starts to 
open, more rapidly than the amount of air, but since air 
is then beginning to flow up the venturi and past the 
throttle disk, this condition just meets the requirements. 

On the idling there is only one adjustment, that of 
the little needle valve which controls the admission of 
idling air. The precise relative positions of the slot and 
the edge of the throttle disk is very important and the 
throttle disk should never be removed. Adjustment of 



the air orifice by the "idle adjusting needle" is all that has 
to be done in service. 

Acceleration Action 

When the throttle disk edge is removed from the 
immediate proximity of the idling slot, suction on the 
latter falls to almost nothing and all the entering air 
comes through the venturi. If the throttle is opened 
quickly there is a pause before the gasoline in the main 
discharge nozzle begins to flow, owing to the inertia of 
the fluid. It is therefore necessary to give an extra 
supply of gasoline at the instant of throttle opening 
which will last just long enough to permit the main 
nozzle to get into action. 

Now the main nozzle is a tube, standing in a small 
cylindrical chamber. Gasoline enters the nozzle from 
the bottom, passing through a small hole in a plug called 
the "acceleration metering nozzle," which will be referred 
to again later. 

In the tube which forms the main discharge nozzle 
there are a few large holes at the top, forming the dis- 



THROTTLE VALVE 
BODY 



LARGE VENTURI 
TUBE 



SMALL VENTURI 
TUBE 



MAIN DISCHARGE 
NOZZLE 



THROTTLE VALVE 

THROTTLE VALVE SHAFT 

IDLE DISCHARGE NOZZLE 



IDLE ADJUSTING NEEDLE 

IDLE TUBE 

AIR INTAKE TO JET 

FLOAT STRAINER 

NEEDLE VALVE 
PLUG / 




NEEDLE VALVE SEAT 



3 



GASOLINE 
CONNECTION 



FLOAT LEVER 
FULCRUM SCREW 

FLOAT NEEDLE VALVE 



GASOLINE CHAMBER 
SCREW PLUG 



ACCELERATING 
WELL 



ACCELERATING WELL 
METERING NOZZLE 



MAIN BODY 

BOI ' . Ml 'i ! RING NOZZLE 



GASOLINE CHANNEL 
PLUGS 



ACCELERATING WELL 
SCREW PLUG 



AIR HORN DRAIN CONNECTION 

Sectional diagram of Stromberg Aviation Engine Carburetor NA-D4 



22 



WRIGHT AERONAUTICAL ENGINES 



fr 



S\ 



■Idle Discharge Nozzle 

.-'Idle Adjusting Needle 




V^ 



WRIGHT AERONAUTICAL ENGINES 



23 



FLOAT 



NEEDLE VALVE PLUG 
■ STRAINER 




NEEDLE VALVE SEAT 
C 
NEEDLE VALVE 



FLOAT LEVER 
FULCRUM SCREW-P" 



jASOL.NE G s A c S R trp M L B UG R 



FLOAT LEVER 
SPACER-B 



Stromberg Float Mechanism 

charge into the venturi, but lower down there are smaller 
holes which simply communicate with the cylindrical 
chamber around the nozzle. When idling, gasoline 
stands inside the main nozzle and flows out through the 
holes into the chamber, for it is from this chamber that 
the idling slot gets its supply of fuel. 

Then, when the throttle is opened suddenly, suction on 
the idling slot stops and the gasoline in the cylindrical 
chamber at once flow^ back into the main nozzle tube. 
The size of the chamber is such that it contains just 
enough fuel to tide over the fraction of a second before 
the full flow starts through the accelerating metering 
nozzle. 

Fully Open Action 

From the description of the acceleration action just 
given it will be obvious that when the chamber around 
the main nozzle is emptied the small holes will be uncov- 
ered to the air in the chamber, although the inside of the 
nozzle will be full of gasoline. Now, when the chamber 
is empty, the pipe leading to the idling slot is also empty, 
and this means that the chamber is open to the atmosphere 
through the orifice which admits air for idling. 

The effect of this is that the uprushing stream of 
gasoline draws in a little air with it and this air is carried 
along in the stream in the form of bubbles. As the 
gasoline passes out into the venturi these bubbles burst 
and are of important assistance in breaking up the liquid 
into fine spray. 

High Speed Adjustment 

It has already been said that the accelerating meter- 
ing nozzle which screws into the bottom of the main 
discharge has a small hole through it. This hole is the 
only communication between the float chamber and the 
engine. It is by varying the size of this hole that the 
maximum gasoline (low is regulated. For any par- 
ticular model of engine there is a correct size for this 
hole which never requires changing. 

There is also a correct size of lar»c venturi which is 



invariable once it has been determined for any given 
design of engine under no circumstances should it be 
changed. 

Mixture Control 

As an airplane ascends the density of the air de- 
creases, but that of the gasoline remains unaltered, so 
there is a tendency for the mixture to grow richer and 
richer. Now the actual power that forces the fuel out 
of the nozzles is the pressure of the atmosphere acting 
on the surface of the fuel in the float chamber. There- 
fore, it is possible to prevent the mixture growing richer 
with increase in altitude, by decreasing the atmospheric 
pressure in the float chamber. 

Now, when the engine is running, the pressure inside 
the large venturi is always lower than that of the out- 
side atmosphere. If the pressure above the fuel in the 
float chamber was the same as that inside the venturi 
there would be no flow of fuel. To get the correct flow 
of fuel it is necessary to have the correct difference in 
pressure between the two points. 

The venturi size is chosen in the first place so that 
on the ground, with atmospheric pressure in the float 
chamber, the flow is correct. The cover of the float 
chamber is airtight and commmunication between the 
air space in the chamber and the outside atmosphere is 
through a quite small hole. In the side of the venturi 
are some small holes which communicate with a pas- 
sage leading to a valve and thence to the air space in the 
float chamber. 

Obviously then, if this valve is opened the suction in 
the venturi starts to draw air away from the float 
chamber, this being made up by air coming in through 
the fixed hole in the float chamber cover. The effect 



VENTURI SUCTION 
SPACE 



CORED CHAMBER 

VENTURI SUCTION PASSAGE 



MIXTURE CONTROL 
VALVE 

MIXTURE CONTROL 
LEVER 

MIXTURE CONTROL 
SLEEVE 




Detail ol mixture control mechanism ol Stromberg 
Carburetor 



24 



WRIGHT AERONAUTICAL ENGINES 



of opening the valve is. therefore, to rarify the air 
in the float chamber and so reduce its pressure on the 
fuel. The valve actually used gives great delicacy of 
action ; when closed the mixture is rich and opening it 
makes the mixture grow leaner. 

The holes in the venturi lead through a passage in 
the carburetor body to a small cylindrical chamber 
in the float chamber cover. Into this is set a steel 
sleeve with two holes in it opposite to each other, one 
larger than the other. There is an annular space between 
the sleeve and the chamber surrounding it. Inside the 
sleeve fits a hollow plug also with two holes in its sides. 
The lower end of the plug is open to the float chamber, 
the upper end is outside the carburetor and has the mix- 
ture control lever attached to it. 

Now the holes in the plug are so placed that on turn- 
ing the plug the small hole in the sleeve is first uncovered. 
When it is about half open the larger hole starts to 
uncover also. There is a small spring and a friction 
disk on the underside of the lever to make the action 
smooth, and to hold the position when set. 



Float System 

The float, although metal, is not the conventional 
cylindrical shape, but is like a ball with flattened sides. 
Attached to it is a lever pivoted on the side of the float 
chamber. As fuel enters, from the top of the float 
chamber, the lever lifts a small monel metal valve and 
shuts off the supply. The carburetor must always be 
fitted so that the air intake is forward and open to the 
direction of flight. Otherwise, when climbing the float 
level will be above that of the nozzles and the fuel flow 
will be excessive. 

With the air intake forward the nozzles are below 
the float level only when diving, and since the throttle is 
then usually almost closed the loss of fuel will be very 
slight as the float cuts off the supply as soon as the small 
excess has spilled over and escaped throught the drain 
overboard. 

When the conditions of flight are such that the pilot 
tends to fall away from his seat, the same force which is 
acting upon him is acting also on the float and therefore 
the float lifts and shuts off the fuel. 



CARBURETOR ADJUSTMENTS 

Possible Carburetor Troubles and How to Check Them 

For Overhaul of Carburetor, See Page 73 



A CARBURETOR which has been operating well can 
become out of order in only two ways. One, and 
'"this is far the most usual, is the presence of dirt in 
the fuel. The other is the loosening of some part, which 
should never occur if full advantage is taken of the lock- 
ing wires and other devices when assembling. 

Therefore adjustment, other than cleaning, should 
only be necessary only when the nature of the fuel is 
changed considerably. A great change in atmospheric 
temperature may call for adjustment of the idling screws. 

Stromberg Instructions 

If idling is irregular, before touching the carburetor 
remove all the spark plugs to see that they are clean and 
that the gaps are all set to 0.020 inch. Then see if ignition 
is regular when engine is speeded up. 

If these two operations are performed and show that 
the ignition is correct, but leaves the idling still irregular, 
then, but not before, try adjusting the idling screws both 
together in order to find out whether it is excessive rich- 
ness or weakness that is causing the trouble. Screwing 
the adjustment in makes it rich and unscrewing makes it 
weaker. 

Too Rich on Idle 

If this test shows that the idling adjustment was too 
rich do not merely readjust the idling screws, since the 
probability is that the excessive richness is caused by dirt 



stopping up the air bleeder holes. Clean these out thor- 
oughly and then see if the original adjustment of the 
idling screws does not give correct idling. 

To check one block of cylinders at a time to see that 
idling is even on both blocks open the pet cocks on the 
manifold belonging to the block it is desired to cut out. 

Too Weak on Idle 

If test of adjustment shows weakness there is a strong 
probability that air is leaking into the manifolds. There- 
fore see that all flange connections in the manifolds are 
tight, not forgetting the expansion gland on the tee, as this 
requires tightening occasionally. 

In replacing the carburetor after overhaul it is easy to 
damage or displace the gaskets at either end of the tee, so 
look to these first. 

If these tests do not disclose the trouble it is practically 
certain that dirt is the cause. 

To Clean 

Remove needle valve plug indicated in the cuts and 
small strainer will be found. If this is quite dirty the gas 
chamber screw plug should also be removed and the float 
bowl flushed out with gasoline in order to make sure that 
the needle valve and seat are clean. 

Should indications of weakness continue after cleaning 
the screen, and if the screen was found very dirty, it will 
be necessary to remove the carburetor from the engine and 
take it apart for detail cleaning. See page 73. 



WRIGHT AERONAUTICAL ENGINES 



25 



Idle Adjustment 

It idling- is poor but acceleration satisfactory first see 
that all manifold flange joints are tight. Examine spark 
plugs for cleanliness and correct gap ; also see that mag- 
neto breaker gap is set at from 0.015 to 0.020 inch. Check 
condition of the screen as described in the last paragraph 
and if found clean then, but not before, adjust for idle by 
means of the two idle adjusting screws shown in cut on 
page 21. Screwing these /';; makes the idling mixture 
richer, unscrewing them makes it weaker. Never attempt 
to adjust for idling on a cold engine. 

Flooding 

If flooding continues after cleaning screen and flush- 
ing out float chamber it will be necessary to take the car- 



buretor apart for examination of the needle valve and 
seat. See overhauling instructions, page 73. 

Cold Weather 

Cold weather will usually call for a richer adjustment 
of the idling screws, but these should be set as lean as 
possible at all times. The table of carburetor settings on 
this page gives the normal requirements for the different 
models of Wright engines. 

Models Models 

Model I E and E-2 H and H-2 

Carburetor Type .N.A.D. 4 N.A.D. 4 N.A.D. 6 

Venturi diam., in 1^ 1 % lyf 

Accelerating nozzle No. 44 No. 30 No. 32 

Body metering nozzle No. 46 No. 42 None 

Head from bottom of tank to carburetor must not be 
less than IS inches, correct pressure for fuel supply is 
2V 2 lbs. 



MODEL A CARBURETION 

Description of Zenith Carburetor D.C. 48 Used on Original 
French Engine and on Wright Model A Engines 



THE Model A Wright engines were supplied with 
the Zenith D. C. 38 carburetor, which, like the car- 
buretors of the later models, is a duplex instru- 
ment, having a single float chamber, but two venturi and 
two complete separate systems, one for each block of 
cylinders. 

The unique feature of the Zenith is the construction 
of the main jet. This consists of a small central nozzle 
surrounded by a tube. Gasoline is supplied to both the 
inner tube and to the outer one, the two streams mixing 
together at the point of discharge. 

The inner tube is connected directly to the float cham- 
ber, which means that the amount of fuel sucked through 
it will increase as the engine speed increases, and its size 
is such that it will supply just about enough for the 
maximum engine speed. Owing to the peculiar character- 
istics of the flow of liquids through nozzles, this means 
that at low engine speeds the fuel supply would be inade- 
quate. Now the outer tube of the nozzle is also connected 
to the float chamber, but not directly, since between the 
two is a plug pierced by a very small hole. This hole 
limits the quantity of fuel that can pass from the float 
chamber to the outer tube. 

Therefore at low speeds and low suction (low speed 
at open throttle, that is) fuel is sucked through both inner 
and outer tubes. Then, as the speed and suction increase, 
the supply through the outer tube soon reaches its maxi- 
mum possible, and as speed increases still more the major 
part of the supply comes through the inner tube. 

The idea of this construction is that the outer tube 
gives the correct flow for low speed but not enough for 



high. The inner tube gives enough for high speed but 
not enough for low. By proportioning the two correctly 
they compensate each other and so give the correct flow 
for all speeds. Changing the little plug between the float 
chamber and the outer tube of the nozzle alters the char- 
acteristic of the combination and this is one of the adjust- 




Diagram of mixture control action of Zenith D. C. 48 
carburetor 



26 



WRIGHT AERONAUTICAL ENGINES 



merits used in setting a carburetor to suit a particular 
design of engine. 

Idling System 

The compound nozzle just described takes care of 
open throttle running only. For idling there is a hole in 
the body of the carburetor which is covered and closed by 
the edge of the throttle disk when the throttle is shut. 
From this hole a small tube leads down into the gasoline 
duct between the float chamber and the outer tube of the 
main nozzle. Surrounding this tube is a "well" and at the 
top of the well there are some small holes through which 
air can enter. 

When the engine is not running, fuel will stand at the 
same level in the well that it does in the float chamber. 
On starting, with the throttle nearly closed, fuel is sucked 
from the well through the idling tube, mixes with the 
small quantity of air coming around the throttle disk and 
so supplies the mixture. 

Now the well, the idling tube and the outer tube of the 
main nozzle are all fed from the same passage, and this 
gets its supply of fuel through the compensating plug. 



which means that the total supply is limited. On opening 
the throttle, fuel immediately is sucked out of the main 
nozzle and, since there is no restriction between the well 
and the nozzle while there is the compensating plug 
between the well and the float chamber, the first effect is 
to empty the well. The throttle remaining open, gasoline 
wid continue to come in through the compensating plug, 
but not fast enough to do more than supply the outer tube 
of the main nozzle, so the well remains empty. Through 
the small holes at the top of the well air will come in, and 
this mixes with the fuel, so that at high speeds the outer 
tube of the main nozzle supplies part gasoline and part 
bubbles of air, the latter being of great assistance in break- 
ing up the fuel into a fine spray. 

Mixture Control 

The flow of fuel through the main nozzle is, of course, 
caused by suction, which is another way of saying that it 
is caused by the pressure of the atmosphere on top of the 
fuel in the float chamber being greater than the pressure 
of the air in the venturi around the tip of the nozzle. The 




Section of Zenith D. C. 48 carburetor. A is the compensating plug. C is the idling jet, which is adjustable at 
points B and D. E and F are inner and outer members of main nozzle. G is the gasoline passage used for idling and 
acceleration, and H the main supply channel. This section is diagrammatic only. 



WRIGHT AERONAUTICAL ENGINES 



27 



richness of the mixture at any speed will depend upon the 
difference in pressure between these two places. 

Connecting the top of the float chamber and the body 
of the carburetor just below the throttle disk is a passage 
having a cock set in it. If this cock is closed the car- 
buretor operates in the conventional way, but if it is 
opened air is sucked away from the float chamber. Con- 
nection between the float chamber and the outer atmos- 
phere is through a comparatively small screened opening, 
so that when the cock is open the suction establishes a 
partial vacuum in the float chamber. This decreases the 
difference in pressure between the float chamber and the 
tip of the nozzle and so reduces the flow of fuel. The 
cock is attached to a control, which the pilot uses to adjust 
the mixture richness either on the ground or during flight. 

Adjustments 

The general instructions for adjustment given on page 
24 apply equally to the Zenith and Stromberg carburetors. 
The procedure for checking correctness of adjustment 
being just the same. In installation the carburetor must 
always be set with the air intake forward, facing the 
direction of travel, for the reasons given on page 24 
under the head "Float Mechanism." 

NA-V6 Stromberg Carburetor 

The NA-V6 Stromberg Carburetor is used on some 
model H and H-3 engines by the U. S. Navy. The 
carburetor outlets are 2^ inch diameter and are arranged 
on either side of the float chamber at 45 degrees from the 
vertical, instead of to the front as in other Stromberg 
carburetors. This allows the fuel jets to be placed on the 
lateral center line of the float, so that the fuel flow is 
not affected by fore and aft inclinations of the plane. The 
float mechanism is similar to other models and a similar 
double venture is used. 

The mixture control is of greater range than the 
NA-D6. The mixture controlling suction is taken from 
a tube projecting up the center of the small venturi, where 
the suction is approximately equal to that on the full jets. 
The mixture control lever is concentric and above the 
throttle control lever. Provision has been made for a 
partial connection of their action in such a way that 
closing the throttle the last half of the way will positively 
move the control lever into the rich position. 

The throttle lever is closed when toward the gasoline 
connection, and this is the rich position of the mixture 
control lever. 

Bijur Electric Starter 

A Bijur Electric Starting motor can be used on models 
E and I engines by using Inclined Magneto Bracket Part 
No. 12369 and Engine Starter Extension Part No. 15284. 

On model E-2, H, H-2 and H-3 use Magneto Support 
Bracket Part No. 12331 and Engine Starter Extension 
Part No. 15284. 

This Inclined Magneto Bracket assembly consists of a 
main drive shaft fitted with internal spline of standard 



design, which will fit Bijur Starting Motor drive shaft. 
Motor is attached direct to magneto bracket with a special 
extension and is held in position by studs supplied with 
same. 

Hand Starting Crank 

On some engine installations it is desirable to have a 
hand starter, particularly for flying boats and seaplanes. 
A hand starter can be supplied and attached to all models 
of Wright engines. The starting crank itself is geared 
down to the engines to facilitate cranking, the gear ratio 
being 7.35 to 1. It is attached directly to the back of the 
magneto bracket, the magneto drive shaft being pro- 
longed and the end of the bracket flanged for this purpose. 

The starting crank is lubricated by oil splashed from 
the lower vertical shaft gear. The starting crank shaft 
is equipped with a spring having a strong outward pres- 
sure which holds the dog out of mesh after engine starts. 
The dog at the front end of the shaft automatically frees 
itself when the engine starts. It is built with ball bear- 
ings and aluminum case. 

There are three types of hand starters used, assembly 
12370 for model E-2, assembly 11727 for model A and 
assembly 12268 for E and I with horizontal brackets. 

To install crank on model E-2 using starting crank 
assembly 12370 with inclined magneto bracket 12331, re- 
move magneto bracket and plate, saving the gasket. 
Remove wire lock and nut from magneto drive shaft, 
assemble threaded end of clutch dog to magneto drive 
shaft and lock with wire lock, then assemble starting 
crank bracket. On models E and I it is preferable to 
remove the horizontal bracket which carries the oil suc- 
tion pump, replacing with inclined magneto bracket 12369 
which has the geared oil pump below. Then attach starter 
12370 as described for E-2. However, a starting crank 
assembly 12268 may be used on E and I without changing 
the horizontal magneto bracket. 

To install starter on models H-2 and H-3 change to 
inclined bracket 12331 then use starting crank 12370. The 
installation is the same as for E-2. Note that if a sylphon 
pump is attached to the end of the crankshaft that no 
starter can be used. Model 11 must have the horizontal 
magneto bracket replaced with inclined bracket 12331, 
then proceed as with H-2 and H-3. 

Model A used a different hand starter part 11727, 
which had a starting magneto geared to the hand crank, 
giving a hot spark as the engine was rotated by the hand 
starter. 

Gasoline and Benzol 

Use gasoline of approximated 68 degrees Baume, 
which has a specific gravity of .7447 and weighs (\02 lbs. 
per gallon. Be careful it is clean and free from water. 
To exclude water strain through chamois, cotton mole- 
skin or cotton twill. The gasoline used at the Wright 
plant for testing has gravity .73 to .76. initial evaporation 
''3 degrees C. or 200 degrees F., end point of evaporation 
309 decrees C. or 590 degrees F. 



28 



WRIGHT AERONAUTICAL ENGINES 



Benzol may be added to the gasoline for any Wright 
engine without change of carburetor nozzles. A mixture 
of 20 per cent, benzol and 80 per cent, gasoline is used at 
the Wright plant for test runs. For compressions above 
?.3 to 1 benzol should be used to prevent preignition. 
With a compression of 6y 2 to 1 it is advised to use 50 
per cent, of benzol. 

CAUTION IN USING BENZOL. Avoid use of 
rubber hose as benzol dissolves rubber and eventually the 
carburetor will be plugged with flakes of rubber. Where 
rubber hose must be used it should be fabric lined. Reject 
any benzol having a zvhitc milky color. White, milky 
benzol is apt to leave a precipitate which may clog car- 
buretor. 

Lubricating Oil 

Care must be taken in the selection of lubricating oil. 
An unsuitable oil may cause expensive damage to the 



engine. The lubricating oil used must be a pure mineral 
hvdrocarbon oil, free from acid or alkali, adulterants and 
impurities. The oil should meet the following specifi- 
cations : 

Flash Point Open Cup — 465 degrees F. minimum. 
Burning Point — 520 degrees F. 

Viscosity (Saybolt) — 105 sec. at 210 degrees F. mini- 
mum. 

Specific Gravity — .886 at 60 degrees F. 
Baume Gravity — 27.5 at 60 degrees F. 
Cold Test— K) degrees F. 
Free Acid — Nil. 

We do not recommend any particular make of oil, but 
there are three oils which have given satisfactory service 
at such times as they have been graded to comply with the 
above specifications. We will upon request gladly advise 
you in regard to any particular oil or give more detailed 
advice on trade oils to purchase. 



SECTION II. 

Installation and Operation 



INSTALLATION SUGGESTIONS 

A Brief Resume of Some of the More Important 
Points Affecting the Performance of an Airplane 



OWING to the extreme rapidity of aircraft develop- 
ment during the war period, there has been in 
the past less co-operation between airplane and 
aviation engine builders than there should have been. 
Many of the most successful fighting planes were little 
better than a makeshift combination of a good design of 
plane with a reliable engine. They could easily have been 
improved upon had time permitted. 

Towards the end of the war co-operation was really 
beginning, but even then planes were being designed to 
take more than one engine, even to be adaptable for either 
an air cooled radial or an eight-cylinder water cooled 
Yee type motor. 

This was an unavoidable war condition, but there is 
no excuse for its continuance. Recent performances have 
amplv proved that the best results are obtained when 
engine and plane engineers work together. 

Common Installation Troubles 

While of little importance for the occasional stunt 
performance, it is vital for continued good operation that 
those parts of the engine which require attention should 
be accessible. The following parts of any engine need 
constant attention and their accessibility is vital to the 
reliability of the ship as a whole. They are : 

The carburetor. The oil strainer. 

The spark plugs. The water pump. 

The magnetos. The fuel pump. 

It should be possible, without doing more than open 
doors in the engine housing, to completely remove the 
carburetor and all the spark plugs. 

There should also be an opening large enough to let 
the oil strainer be removed and replaced, not forgetting 
that a fair-sized wrench has to be used for this operation. 

The ends of the magnetos should have openings oppo- 
site to them through which the action of the breaker 
points can be observed directly and clearly. Also, in the 
case of Wright engines, it is desirable when possible to 
provide access to the rear end of the engine so that the 
magneto bracket with its two magnetos can be removed 
as a complete assembly, although, of course, this is much 
less important than access to the breaker boxes and dis- 
tributor heads. 

Radiation 

The majority of airplane engines are under-cooled 
both as regards water and oil. The construction of 
radiators is improving rapidly and much useful data is 
now available as to the cooling requirements of different 
engines. This subject has not yet reached a stage of exact- 
ness, but in laying out a new airplane it is desirable to err 



on the side of over-cooling. It should not be overlooked 
that, while the desire to keep down the radiator dimen- 
sions is perfectly natural in so far as they affect head 
resistance, still the performance of the plane depends upon 
the power output of the engine at least as much as upon 
the resistance. 

For E or E-2 engines the radiator should have not less 
than 150 square feet cooling surface for a nose radiator 
with 5-inch core and not less than 120 square feet cooling 
surface for a free air radiator with 9-inch core. 

For H, H-2 and H-3 engines the radiator should have 
not less than 225 square feet cooling surface for nose 
with 5-inch core, nor less than 180 square feet for free 
air with 9-inch core. 

This is assuming hex. end copper tubes .268-inch 
diameter with engine cowled, radiator in slip stream, 
cowling lowered at least 10 per cent, more than air area 
of core, and free water flow through radiator at least 25 
per cent, in excess of pump capacity as shown in specifi- 
cations sheets at back of book. 

Oil tanks should be placed so as to be thoroughly air 
cooled. 

Piping and Controls 

Compactness in an engine installation generally makes 
for minimum weight, for accessibility and for reliability. 
It is easy to obtain in designing a new plane if considera- 
tion is given to every detail. 

A good deal of trouble in the air has been caused by 
the loosening of pipe joints and connections either in gaso- 
line, oil or water systems. If fuel, oil and water pipes are 
short and straight they are much less likely to give trouble 
than if they are long and sinuous. Often a slight change 
in the originally laid out position for, say the oil tank, 
will greatly simplify the piping. 

It should also be remembered that practicallv all pipe 
joints have to be made after the engine is in position, and 
they should therefore be accessible. 

It is believed that the raising of the magnetos on 
Wright engines so that the bed timbers can be carried 
straight back, to any length the plane designer desires, will 
be of very real assistance in simplifying installation. 

To controls, which comprise the throttle and the mix- 
ture richness adjustment, those which are straightest and 
have fewest links are usually the best. Experience shows 
that the delicacy of control varies very much in different 
ships and it is urged that the pilot's levers be given ample 
travel to enable engine speed and mixture richness to he 
adjusted accurately and easily. 

Control rods or links should also be so placed and 
proportioned that it is possible to remove the carburetor 
without breaking more than one link. 



32 



WRIGHT AERONAUTICAL ENGINES 









Propeller Data 


for Various 


Wright Er 


gined Airplanes 






Airplane 


Engine 
Model 


No. of Blad 


es Tractor or 
Pusher 


Diameter 


Mean Pitch 
(At 0.6 R) 


Approximate 

Max. Speed 

M. P. H. 


Airplane Performance 
Maximum Climb 
Ft./Min. 


TN-4H.... - 


I 


2 


T 


8—6" 


5.76' 


(Estimated) 

93 






VE-7 ---. 


E 


2 


T 


8'— 6" 


6.04' 


106 




950 


VE-7 - 


E 


2 


T 


8'— 8" 


6.20' 


114 




990 


DH-4B 


H 


2 


T 


9' 2" 


5.85' 


115 




1010 ' 


Ordnance Type 


D 


H 


2 


T 


8'— 6" 


7.10' 


147 




1450 


Loening, 


M-8 .. 




H 


2 


T 


9'_0" 


7.29' 


143.5 




1520 


Thomas- 


Morse, 


MB-3 


H-2 


2 


T 


8'— 6" 


8.10' 


152 




1970 


Y. C. P 


-1 




H 


~> 


T 


9'_ 0" 


6.85' 


154 




1720 


Bristol F 


iehter, 


1918, Alt- 


H 


2 


T 


9' 2" 


6.67' 


116 




1190 


XB-1A ...- -- 


H-2 


2 


T 


9'— 0" 


6.50' 


133 




1300 



Pipes and controls should be placed so that there is no 
risk of their chafing against any part of the fuselage. This 
has been another frequent cause of forced landings and 
of fires. 

Pusher Installations 

Two important points have sometimes been overlooked 
in installations of the pusher type. One of these is that 
the carburetor air intake must face forward, in the direc- 
tion of travel. This is essential in order that the nozzles 
give the proper supply of fuel under different flying con- 
ditions and is explained in detail in the carburetor descrip- 
tion on page 24. 

The other is that the water connections on the cylin- 
ders are changed so that the outlet to the radiator is situ- 
ated at the magneto end of the engine, since this is the 
highest point during climbing, when maximum radiation 
is required. 

Propellers 

Since trial alone can as yet decide the best propeller 
combination for any particular airplane and engine it is 
not possible to offer any precise suggestions as to equip- 
ment for Wright engines. 

The table at the top of this pag"e gives some slight 
particulars of propellers which have been found suitable 
in eleven different Wright engine installations and this 
may be of some use to desginers of new ships. More 
detailed information and more precise suggestion can be 
given by the Engineering Department of the Wright 
Aeronautical Corporation if the general characteristics 
and desired performance of a new design is known. 

Co-operation 

The Wright Aeronautical Corporation is always 
anxious to co-operate fully with designers of new air- 
planes and to place at their disposal complete details of 
installations which have proved particularly satisfactory. 
The company's engineers have given much time and study 
to this subject, believing that the success of both engines 
and planes depends to a very large extent indeed upon 
their entire suitability for each other. 



Wrench as used on both 
nuts for removing hub after 
unlocking nuts. 




Hub wrench as used for 
unlocking hub 




Use of hub wrench 



PROPELLER ATTACHMENT 

Instructions for Care of Propeller Hubs 
and Mounting Propellers in Hubs 



IN placing a propeller hub in a propeller, always put 
the kevwav of the hub in the axis of the blades. 
Starting the engine by cranking is facilitated if the 
propeller is keyed in this position for "carrying over com- 
pression." Moreover, this recommendation is of vital 
importance since this position has been adopted for 




Tightening the Hub Nuts I, E, E-2, H, H-2 and H-3 

There is one inner propeller hub nut and one outer 
nut holding the propeller hub on the crankshaft, they 
being locked together with a lock wire. 

To fasten the hub on the crankshaft taper: 



Using Model A hub wrench 



Location of keyway in propeller hub 

adjustment of the layout for bring the machine gun 
through the path of the propeller. 

Fit of Hub in Propeller 

The hub should be a light press fit in the pro- 
peller. Hubs can be pressed in the propeller with an 
arbour press. If no arbour press is available, the 
hubs may be pressed into the propeller by using a 
large bolt and two block with holes drilled in their 
centre for the bolt. Place the bolt through the 
centre of the hub and through the centre of the 
propeller, also through the blocks with a block on 
each end of the bolt. See that the blocks rest so as 
to bring the strain directly over the sleeve portion 
of the hub. Draw down on the block by turning 
the nut on the bolt. Hubs should not be driven 
into propellers or removed with a hammer or 
mallet, as there is danger of splitting the pro- 
peller. 

Mounting on Crankshaft 

The mounting of the hub on the taper of the 
crankshaft requires very particular precautions ; 
the hub supplied with each engine has been fitted 
to its taper by lapping with emery and oil while 
the key is removed. The hub and 
crankshaft taper is then thoroughly 
cleaned and the key replaced, making «f 
sure to lubricate the taper and hub 
with tallow or oil and graphite. This 
operation should be strictly adhered to 
each time a new hub or one that shows 
wear is placed on the crankshaft ; 
always remembering that a bad fit 
rapidly develops play and if run in 
this condition will do great damage. Tracking 





and balancing stand 



1. Insert the inner nut in the outer nut, so that 
both have their hexagon heads at the same end. 

2. The thread on the outside of the outer nut 
fits the thread on the inside of the hub, screw the 
nut into the hub while the inner nut is still in the 
outer nut. This can be screwed all the way in 
until it bottoms and then backed off about three or 
four threads. 

3. Place the hub on the crankshaft taper and 
start the inner nut on the thread on the end of the 
crankshaft by the aid of the wrench WA, which is 
found in the tool equipment ; pull the nut home ; this 
draws the hub on the crankshaft taper. 

4. After the hub is drawn on the taper, the 
inner nut is locked in place by drawing up the 
outer nut, the nuts are then locked together by 
the lock spring wire, and the operation is com- 
pleted. 

Model A has one nut threaded inside and 
out, the outside thread fitting the hub, the in- 
side thread fitting the crankshaft. Before put- 
ting the hub on the shaft screw the nut into 
the hub about 5 threads, then place hub on 

shaft and catch inner thread on shaft. 

screw home with wrench and safety 

wire. 

Proper Balance 

A faulty balance or fluttering of 
the propeller always causes vibration. 
As soon as this condition is encoun- 
tered, correct the balance with care 
and also the pitch, using a tracking 
stand of the type shown on this page. 



UNPACKING— ALL MODELS 



TWO different forms of packing are used, one for 
domestic shipment and the other for export. The 
latter is, of course, the heavier style. The follow- 
ing tabulation gives the dimensions and approximate 
weights of engines packed both ways : 

Domestic Shipping 

Models Models 

A, E, I, E-2 H, H-2 and H-3 

Length - 60 in. 60 in. 

Width of case - 38 in. 44 in. 

Height - -- 40 in. 44 in. 

Weight - 870 lbs. 950 lbs. 

Displacement 52 cu. ft. 64 cu. ft. 

Export Shipping 

Length 55 in. 

Width of case 38 in. 

Height - 40 in. 

Weight 1040 lbs. 

Displacement 53 cu. ft. 

Unpacking 

1. Remove front end of box by taking out wood 
screws. 

2. Remove lag screws which hold in box a skid to 
which the engine is attached and pull skid and engine 
out. 

3. Remove engine from skid, lifting it by two cables 
placed around cylinder blocks as shown in illustrations on 
pages 35 and 36. Lift with hoist. 

Cleaning Engine 

1. Remove paper wrapping from: 

Propeller hub. 
Water pump. 
Air pump. 
Magnetos. 
Do not remove any other coverings for detail parts. 

2. Wash off protecting coating of heavy oil. This is 
done most effectively by a spray of gasoline. If it is 
necessary to use gasoline dampened rags, be sure rags are 
clean and free from grit. 

3. Remove all remaining wrappings and the fiber 
covers which are over all exhaust and water pipe flanges. 



4. Remove spark plugs and turn engine over as fast as 
practicable in order to remove oil with which interior of 
cylinders is flushed before shipping. 



NEVER REST ENGINE ON ANYTHING 
EXCEPT A PROPER ENGINE BED. 

Preparation of Engines for Shipment or Storage 

Drain the float chamber by running engine until it 
stops. Remove exhaust pipes and at least one plug in 
each cylinder. Rotate until engine is thoroughly slushed 
with oil. Thoroughly drain off all water. Remove the 
large 33 M/M plug on each camshaft cover to wipe off 
camshaft, etc. ; then slush thoroughly and replace cover. 
Remove water pump covers, take out the impellers, wipe 
or blow dry with air. Plow compressed air through water 
jackets to carry away any slight amount of water. Grease 
water pump impeller with vaseline and replace. Pour 
one pint of cylinder oil of the grade used on engine in 
each cylinder. Remove cam covers and grease camshafts, 
valve tappets and gears with vaseline. Slush all exposed 
steel parts with E. F. Houghton's "Rust Veto Soft," 
applying with a brush, or by dipping, at a temperature of 
110 degrees to 125 degrees F. Remove propeller hub as- 
semblies and slush hub and shaft. Replace hub nuts hand 
tight. Wrap all exposed holes, such as cylinder water 
outlets, with oiled paper. Seal exhaust openings with a 
plate. After slushing, wrap the carburetor assembly, ver- 
tical shaft housings, propeller hub and magneto bracket 
assembly with oiled paper securely tied. In slushing the 
magneto couplings, care must be taken to cover all the 
surfaces. This can only be done by turning the engine 
over while it is being slushed. 

Houghton's "Rust Veto Soft" was selected for use at 
the Wright plant in July, 1921, after careful experiments 
on 21 of the best-known slushing oils and compounds. 

An engine treated in this manner should be free from 
danger of severe rusting for a moderate period, but if the 
engine is to be placed in storage, it should be immediately 
unboxed when received and torn down, and all parts, in- 
ternal and external, thoroughly slushed. 

Whether for long or short storage periods, it is 
recommended that the engines be stored out of the boxes 
or at least that the ends of the boxes be removed to 
insure thorough ventilation. 



INSTALLING ENGINE IN FUSELAGE 

Precise Instructions for Mounting 
Engine and Making Ready for Flight 

Precautions to Be Taken in the Layout of Controls When Designing the Airplane 

Are Given on Page 3 1 



EASE of engine installation should be studied in air- 
plane design, and general hints regarding this phase 
are given on page 31. The instructions following 
give in proper sequence the operations of installation and 
apply to practically all forms of aircraft. 

Bolts Required 

The bolts for holding the engine to its bed timbers 
should, of course, be of good quality steel. There are 
required : 16 bolts, ^-inch diameter ; 32 hardened flat 
washers, 16 cotter pins, 16 castellated nuts. 

Procedure for mounting is as follows : 

1. Check distance between bed timbers and parallelism 
both for distance apart and for level. If the bed timbers 
are not perfectly true they must be made so or the crank- 
case will be strained in bolting down. 

2. The holes in the bed timbers for the bolts should be 
a tight fit, so that the bolts require to be driven in. The 
spacing of the holes should be sufficiently accurate to 
allow the engine to set readily over the bolts. 

3. Cut two fiber strips about ^\-inch thick. Mark off 
and drill clearance holes for bolts, and attach to bed tim- 
bers with a few flat head tacks. 

4. Insert holding-down bolts from under side of bed- 
timbers, placing one washer under the head. 

5. Lower engine into place. 




Showing proper method of attaching rope for lifting engine 



6. Apply second washer and nut to all bolts. 

7. Tighten down nuts gradually and in rotation. Never 
draw up any one nut much tighter than the next. 

8. Apply cotter pins of correct size and make sure they 
are well spread. 

Attaching Controls 

After the engine is bolted down the exact procedure, 
of course, varies with the different installations. Hose 
connections are very important indeed, since should any of 
them loosen in flight a forced landing is inevitable. There- 
fore, in deciding procedure particular attention should be 
given to mounting radiators, tanks and so on in such 
sequence that hose connections are all capable of being 
made thoroughly well. 

Making Hose Joints 

The sizes of hose required for each model of engine 
will be found tabulated on page 76 under the two heads 
"Water System" and "Lubrication System." It is impos- 
sible to make a safe connection with hose that is either too 
large or too small. 

The fit of the hose clamps on the outside of the hose, 
and the condition of the clamping bolts and nuts, should 
be checked before application. 

Water Connections 

On the water pumps there are three branches for hose. 
The larger is for the suction line and should be connected 
to the bottom of the radiator by a copper pipe, with hose 
connections. On the lower, outside, rear corners of the 
cylinder blocks are flanged holes to which are attached 
copper pipes which lead downwards to the water pump, 
being connected to the pump by short lengths of hose. 

In some installations, instead of the copper pipes small 
aluminum castings have been attached to the cylinders and 
long rubber hose connections made to the pump. This, 
however, is not such good practice, as the long hose is 
liable to chafe against some part of the fuselage, while 
the copper pipes, having rigidity, can be bent in close to 
the crankcase and kept away from the fuselage. 

The top of the radiator must be connected by copper 
pipes and hose to the two upper, front corners of the cylin- 
der blocks. It is important that (he water enter at the 
lower rear ends and escape from the upper front ends, as 
otherwise the cooling will he uneven and probably inade- 
quate at some point. 

Installing Pusher Type 

Water pipe connect ions must be reversed when the 
engine is being used as a pusher. That is to say the con- 
nections from the water pump must go to the lower front 



36 



WRIGHT AERONAUTICAL ENGINES 



end of the cylinders, and the outlet from the upper 
rear end ; using the terms front and rear in accordance 
with conventional phrasing, which always calls the pro- 
peller end of the engine the front end. 

Model A 

Note that there are four connections on the Model A 
water pump instead of three, these being two outlets and 
two intakes. 

Manifold Jacket 

On E-2 and H-3 engines, the manifold jacket piping 
is carried from the upper front corners ( propeller end ) 
of the cylinder blocks by two connections to the jacket and 
from rear side of jacket by a single pipe to the intake side 
of water pump. This piping is furnished as part of the 
engine. On older models, two nozzles project horizon- 
tally from the upper rear corners of the cylinder blocks, 
and should be connected to nozzles on the rear of the 
manifold jacket by copper pipes with hose connections on 
each end. The jacket outlet should be connected to the 
intake side of water pump as on E-2 ( drawing on request ) 
and not to top of radiator as in past practice. This is in 
order to insure circulation. 

Thermometer Connection 

The maximum water temperature should be indicated 
by the thermometer on the instrument board, and to 
ensure this being the case the thermometer should be con- 
nected to the top of the radiator direct. Care must be 
taken that the bulb of the thermometer is actually in the 
zvatcr or it will not show the true temperature. 

Oil Piping, Models H, H-2 and H-3 

On these three models the oil pipe connections are as 
follows : 

1. From pressure pump intake (located on right hand 
side of gear pump front) to bottom of oil tank. 

2. From suction pump outlet (located on right hand 
side of gear pump at extreme rear end of engine) to oil 
radiator. 

3. From oil radiator to top of oil tank. 

Oil Piping, Model E-2 

On this model the oil pipe connections are as follows : 

1. From pressure pump intake (located on left side 
of oil pump) to bottom of oil tank. 

2. From suction pump outlet (located on right side 
of oil pump) to oil radiator. 

3. From oil radiator to top of oil tank. 

There are two nozzles for hose on the oil pump base, 
and the copper pipes leading to tank and radiator should 
be joined by pieces of hose. 

For connection to the pressure gauge on the instru- 
ment board there is a nozzle on the right side of the 
crankcase low down toward the rear. Connection is made 
by small diameter copper pipe and hose. 




Method of slinging engine 

Oil Piping, Models E and I 

On these two models the oil connections are as 
follows : 

1. From pressure pump intake to bottom of oil 
tank. 

2. From plug in bottom of crankcase to suction 
(left hand) side of gear pump at extreme rear end 
of engine. 

3. From delivery side of gear pump to oil radiator. 

4. From oil radiator to top of tank. 

All the connections on the engine are nozzles suitable 
for rubber hose. All copper pipes should be made of 
short lengths joined by pieces of hose. For connection 
to the pressure gauge on the instrument board there is a 
nozzle on the right side of the crankcase, low down 
towards the rear. Connection is made by small diameter 
copper pipe and hose. 

Oil Piping, Model A 

In the rare cases where no oil radiator is used there is 
no external piping, but in the majority of Model A instal- 
lations the oil radiator is situated directly beneath the 
crankcase and is connected thereto by a large diameter 
piece of hose. The radiator outlet is then connected to the 
pressure pump intake at the rear end of the crankcase, by 
copper pipe and hose. 

There is no oil tank in Model A installations, unless it 
is entirelv separate from the circulation system and 



WRIGHT AERONAUTICAL ENGINES 



37 



merely contains a reserve supply which the pilot can admit 
to the crankcase by hand. 

Pressure gauge connection on Model A is made by 
small diameter copper pipe and hose from a nozzle sit- 
uated toward the front end of the crankcase. There is a 
nipple for a flanged copper pipe on the crankcase ; this 
should be fitted with a short piece of pipe, over which the 
hose connection is made. 

Gasoline Connections 

Most of the carburetors which are on old Wright 
engines, and all those on newer models, have a nozzle 
on the carburetor to which the gasoline line is attached 
by a fabric hose. If the carburetor has a conventional 
pipe connection this should be provided with a very short 
length of copper pipe and a hose joint made as close as 
possible to the carburetor. 

Although all carburetors are supplied with a fuel 
strainer, it is always unwise to rely upon this alone, partly 
because this screen is necessarily small and partly because 
it is almost always inaccessible. There are several excel- 
lent strainers made for airplane work, and one of these 
should be inserted in the gasoline line at some point where 
it is easy to get at for cleaning. 

All carburetors are supplied with a drain which 
removes excess gasoline and prevents its accumulation in 
the air intake. Most of the carburetors have a nozzle for 
a hose connection and some have two such nozzles. A few 
of the older instruments have a conventional pipe joint 
instead of the nozzle and in such cases a hose "break" in 
the line should be made as close as possible to the car- 
buretor. 

Care must be observed in fitting the drain pipe or 
pipes, first to see that they have a continuous drop from 
carburetor to outlet, and second that the outlet is well back 
on the underside of the fuselage and as far as possible 
away from the exhaust pipes. 

An air screen is usually fitted to the carburetor intake, 
but this is not a part of the engine. When used it should 
be large enough in area to insure that the intake is not 
choked. In most installations it consists of a cylindrical 
wire mesh screen about a foot long with a solid end, the 
opposite open end being clipped to the carburetor by a sort 
of hose clamp and the solid end furnished with lugs which 
can be attached to some- point toward the end of the 
cylinders. 

It is, however, more important to make sure that the 
carburetor drain operates properly, since it is only when 
there is an accumulation of gasoline in the intake that a 
flame of a dangerous sort can be caused to blow back. 

Carburetor Controls 

There are two controls on the carburetor, the throttle 
and the mixture control. No special instructions are 
necessary for connecting these to the pilot's control levers 
in the cockpit, except that they must be as straight and 
simple as possible. Make sure after installation that the 
throttle and mixture levers on the carburetor work 
smoothlv and over their whole ranee. 



Also make sure that to get the full range on the car- 
buretor end the maximum amount of travel is also used at 
the cockpit end. If only part of the possible travel of the 
pilot's control levers is used to cause the whole travel on 
the carburetor, then the delicacy of the control is injured. 
Care should also be observed that there is as small as 
possible an amount of play or lost motion in the controls 
and that everything is thoroughly cotter-pinned. 

Spark Control 

Model H is the only engine to which a spark control is 
fitted. This is not connected to the cockpit and is only 
used for starting, access to it usually being obtained by a 
small opening in the side of the fuselage. It is not an 
essential control even on Model H and may be set perma- 
nently in the advanced position if desired. (Cut page 19.) 

Tachometer Shaft 

The tachometer drive connection, which is part of the 
engine, is described on page 9. In most installations it is 
placed on the left hand camshaft. 

Before attaching the flexible shaft see that the little 
shaft in the adaptor has about 0.01 in end play. 

Then see that the nut on the flexible shaft is a good fit 
on the adaptor. 

Check the fit of the tongue on the end of the flexible 
shaft to see that it slides easily into the slot. If the 
adaptor has been removed from the camshaft cover into 
which it is screwed, great care must be taken in replacing 
it to make sure that little shaft engages properly with the 
camshaft end. If the tongue and slot inside do not meet 
squarely it is easy to damage the connection while screw- 
ing in the adaptor. 

If the adaptor is changed from one side to the other, 
make sure that the plug which closes the unused hole is 
not forgotten. 

Wiring 

The cockpit switch should have three terminals, of 
which one is to be wired to a ground on some part of the 
engine, and the other two are connected to the respective 
terminals on the magneto breaker boxes. Be sure that all 
connections are thoroughly tight and, if metal covered 
wire is used, be sure that this is stripped back or taped 
far enough at the magneto terminal ends to make certain 
that vibration cannot cause an accidental ground. 

Starting Magneto 

This usually has two terminals, one of which must be 
firmly grounded to some part of the engine. The other is 
connected to the center of the distributor of one of the 
engine magnetos. If there is no ground terminal on the 
starting magneto, it is essential to run a wire from the 
body of the starting magneto to some part of the engine. 

Note particularly that it is customary to wire the mag- 
netos so that one of them fires all the plugs on the inner 
side of the cylinders (in the Yee) and the other all the 
outside plugs. Since the inside plugs are less liable to get 
oily, the starting magneto should always be attached to the 
right-hand magneto, which always fires the inside set oi 
plugs. This is clearly shown in the wiring diagram. 



STARTING ENGINE 

Proceedings to Be Followed After Installing a New 
Engine and Precautions to Be Taken at Every Start 



WHEN starting a new engine or an engine which 
has just been overhauled it is necessary to observe 
a few points which do not need to be watched so 
closely at every time of starting. In the following the 
instructions for starting a new engine, or one which has 
just been overhauled, are given first. Precautions to be 
taken at every start make a smaller list which succeeds. 

Starting New Engine 

1. Fill radiator and water system and inspect carefully 
for leaks. If any hose in the water system shows signs of 
leakage it should be made tight before doing anything 
further. 

2. Fill oil tank. Turn engine over a few times by 
hand to make sure oil pumps and piping are full of oil. 
Inspect carefully for leaks. See that vent in oil tank is 
free and clear. 

3. Remove gasoline supply line from tank and car- 
buretor and blow or flush it out. In the case of installing 
an overhauled engine or a new engine in an old plane it is 
also wise to flush gas tank itself in order to be sure that 
gasoline system is free from dirt or water. 

4. Replace gas line, fill tank and inspect for leaks. 

5. Remove all spark plugs and check setting of points. 
Gap should be 0.020. 

6. See that magneto ground wire connections are clean 
and tight ; if they are not it may be impossible to properly 
switch off the ignition, making starting rather dangerous. 

7. While plugs are out of cylinders check starting 
magneto action. If spark is weak look to ground wire, 
which should firmly connect the body of the starting mag- 
neto with some part of the engine itself. 

8. Squirt a small quantity of oil in each cylinder. 
About one tablespoonful is the correct amount. 

9. Replace spark plugs and connect wires. 

Final Starting 

The nine points described above are preliminary opera- 
tions. Having checked over all of them the engine is 
ready to be started. It is very important that the remain- 
ing six actions listed hereunder be performed as rapidly 
as possible. Hesitation between one and another is likely 
to prevent a start from being obtained. 

10. Prime through all four of the pet cocks on the 
intake manifolds. Practice is necessary to be sure that 
the engine is neither over nor under primed. The correct 
quantity is given if the cup on the cock is filled and 
emptied four times. As it is more convenient to use a 
squirt can, leaving the cock open and injecting" through it, 
a trial should be made to see how many "squirts" corre- 
spond to the proper quantity. Correct priming makes all 
the difference between easv and quick starting and failure 



to start ; so it is well worth while to take a little trouble 
to get the proper degree of prime. Do not over prime. 

11. Close mixture control to rich position. 

12. Open throttle slightly. The correct opening is 
given when the end of the throttle lever on the carburetor 
has moved one-eighth of an inch from the. dead closed 
position. 

13. See that ignition switch is in "off" position. 

14. Turn engine over four or five complete revolu- 
tions as fast as possible and immediately step back, calling 
out at the same time. 

15. Switch on and revolve starting magneto as fast 
as possible. 

Note — It is essential to perform these last two opera- 
tions as rapidly as possible. Pulling over the engine 
slowly, or pausing after the last pull and before spinning 
the starting magneto, is almost sure to result in failure to 
start. 

Failure to Start • 

If engine does not start after several trials do not 
repeat priming until possible causes for failure have been 
checked over. 

After Starting 

Allow engine to run on very low throttle. Never open 
throttle wide immediately after starting, as this is certain 
to cause injury. Too rapid opening up is injurious to 
valves and pistons because it heats them up too quickly. 
It is also injurious to all the moving parts because the oil 
is not in good lubricating condition till it has warmed up 
and been thoroughly distributed throughout the system, 
a thing which takes some appreciable time. 

A new or recently overhauled engine should never be 
flown till it has idled on the ground for at least fifteen 
minutes. 

During the warming up period each three or four min- 
utes the engine should be speeded up to 1,000 or 1,200 
revolutions for the purpose of clearing the oil off the 
spark plugs. Such opening up should be of very short 
duration ; just a second or two is sufficient for the purpose. 

After the first five minutes of idling the speed may be 
increased little by little, till at the end of fifteen minutes 
the engine will be running steadily at 1,200 revolutions. 

In cold weather be sure to cover water and oil radia- 
tors, as warming up will otherwise take altogether too 
long. 

During the warming up run check ignition once or 
twice to see whether firing is regular on either of the two 
magnetos alone. Never leave the ground unless either 
magneto alone will fire perfectlv. 



WRIGHT AERONAUTICAL ENGINES 



39 



Inspection for leaks in oil. gasoline and water lines 
should be made several times during the run, or at least 
before commencing a flight. 

If gasoline is fed under air pressure and the engine 
has been a long time out of use it is possible that the 
leather in the air pump will require oiling. The air pres- 
sure regulating valve is also liable to need cleaning or 
adjustment. 

After warming up the oil gauge should show at least 
50 pounds pressure and not more than 100 pounds. 



After warming up the water outlet temperature should 
be not less than 90 degrees F. or 32 degrees C, and not 
more than 110 degrees F. or 43 degrees C. Make sure 
that bulb of thermometer is actually in the water and not 
merely in the air over the water. 

Before leaving the ground it is necessary to see that 
the mixture control is set to the leanest possible position. 
To check this the throttle should be opened wide and the 
mixture lever moved in the leaning direction till the engine 
just begins to slow down. Then richen slightly till maxi- 
mum revolutions are again attained. 



NORMAL STARTING 



1. Fill with water, oil and gasoline. 

2. Prime each of the four pet cocks, being sure to give 
the correct quantity, which is four times the contents of 
the cup on the cock. See No. 10 in instructions for start- 
ing a new engine. 

3. Close mixture control to rich position. 

4. Open throttle lever about one-eighth of an inch on 
end of carburetor throttle lever. 

5. See that ignition switch is in off position. 

6. Turn engine over two or three complete revolutions 
as rapidly as possible, and immediately stand clear and 
call. 

7. Switch on and revolve starting magneto as fast as 
possible. 

After Starting 

Idle at from 800 to 1,200 revolutions till water outlet 
temperature is at least 32 degrees C. or 90 degrees F. and 
when warmed up see that oil pressure is not less than 50 
pounds. 

Open engine wide just before taking off and move 
mixture control toward the lean position till the motor 
just begins to slow down. Then richen slightly till maxi- 
mum revolutions are attained. 

Before taking off check ignition to see that either mag- 
neto alone will fire regularly. 



Cold Weather Starting 

Fill radiator and engine with hot water, 
half full of hot oil. 



Fill oil tank 



Economy in Flight 

Considerable saving in gas can be gained in cross 
country flight by careful regulation of mixture, keeping 
it as lean as possible. PARTICULARLY AT PART 
THROTTLE OPENING. 



Steady Running 

All makes of engines vibrate more at some speeds 
than at other speeds. The speed of maximum vibration 
in the air should be ascertained and then care should be 
taken to avoid running at that speed. Careful manipula- 
tion of the mixture control on Wright engines, at low 
altitudes and at part throttle opening, will prevent objec- 
tionable vibration. 



Failure to Start 

1. Check air pressure in gas tank — there should be a 
minimum of 2 pounds. 

2. Try flooding carburetor to see if lines are free. 

3. Check starting magneto as to ground wire. 

4. Check gap in spark plugs to see if points are not 
too wide or too close, should be .020 gap. 

5. Look over breaker cam and points as to adjust- 
ments — points should have .020 clearance. 

6. Look over brushes in distributors — see if they are 
dirty. 



SECTION III. 

Overhaul and Repair Instructions 



42 



WRIGHT AERONAUTICAL ENGINES 






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ENGINE DISASSEMBLY 

Complete Directions for Tearing Down Wright 
Engines in the Most Efficient Manner 



THE sequence of operations given in the following" 
directions has been chosen as the best and most 
efficient after experience gained on thousands of 
overhauls in many different base repair shops, as well as 
in the factory. 

The procedure differs considerably from factory prac- 
tice in that it eliminates as far as possible the use of special 
fixtures and of elaborate special tools. 

It may be thought by the reader that too much stress 
is laid upon certain small points, but the greatest care has 
been caken to eliminate everything that is not really neces- 
sary. Vk here small points are emphasized it is because 
long experience has shown them to be of real importance. 

Fits and Clearances 

These are a case in point. In rebuilding an engine the 
clearances specified should be adhered to as carefully as 
possible. The power, durability and reliability of the 
engine depend upon them, and they have a great effect 
on the oil and fuel consumption. This is especially true 
of the valves and valve mechanism. The valves are 
always the weakest point of an aviation engine and the 
number of hours which can be flown without overhaul 
depends largely upon the accuracy of the valve fitting at 
assembly. 

Special Tools 

In addition to the few tools sent out with every engine 
there is a larger kit for each model of engine, which can 
be obtained from the Wright Aeronautical Corporation. 
This kit consists of tools designed specially for field serv- 
ice, is not expensive, and its use is advisable wherever 
frequent overhauling is done, as the special wrenches, etc., 
are not only quicker to use, but are less likely to do dam- 
age to motor parts, an ever present possibility with ordi- 
nary adjustable tools. 

The kits comprise, first, a number of tools adaptable 
to all of the models of Wright engines, and then supple- 
mentary sets caring for parts peculiar to one model only. 
These tools are listed on page 78 in such a way that 
kits necessary for any one model or for any combination 
of two models can be found. In the overhauling instruc- 
tions frequent mention is made of these tools and it is 
assumed they will be employed. 

Cleanliness 

Owing to the heavy pressures which prevail through- 
out an aviation motor in operation, the smallest amount of 
dirt in the oil is liable to do excessive damage. Thus 
complete overhaul should never be attempted anywhere 
but in a building that can be kept free from dust. 

It is strongly recommended that the special system for 
washing parts (described on page 48) be used, for the cost 



of installing it will very soon be recovered in the longer 
life it will give the engines. Also, while the equipment 
may sound a little elaborate, it is quicker to clean parts 
with it than by haphazard methods. 

Tearing Down 

The instructions following refer primarily to models 
H-3 and E-2, but apply equally to the other models 
except where noted. In overhauling a Model A, E or I, 
follow the directions here and refer to the supplements 
when reference to them is encountered. 

Mounting Engine 

After removal from the plane the engine must be 
placed for overhaul on a stand which will support it on a 
bed similar to the plane bed. Far the most convenient 
stand to use is the wooden tilting stand illustrated on 
page 42. This can be made up by any carpenter and fits 
all models. To use it the engine is placed on the bed and 
held down by three or four clamps. It can be worked on 
thus for the first stages of disassembly, and when the 
removal of the cylinders is reached the whole stand, 
engine and all, is rocked over till it rests on the side legs, 
which brings one or the other of the blocks of cylinders 
into a vertical position. Blue prints of the details of the 
tilting engine stand can be obtained from the Service 
Department of the Wright Aeronautical Corporation. 

Leave Parts Together 

Throughout the tear-down replace all nuts and screws 
wherever possible. This is good practice always, but is 
particularly so with the close fits of an aviation engine. 
Nuts replaced on their threads immediately and so kept 
always on the same bolt or stud will always do up more 
easily on reassembly and the threads will last longer. 

Disassembly 

1. Remove carburetor. Loosen but do not remove 
four nuts holding central portion of intake manifold to 
cylinder branches. Remove support bracket underneath 
carburetor if there is such a part ; it is not always em- 
ployed. 

2. Lift carburetor directly upward as shown in the 
cut, loosening it by gentle tapping. Send the carburetor 
to carburetor department for cleaning. Instructions for 
carburetor overhaul are given on page 7c>. 

3. Remove all spark plugs. 

4. Remove magneto distributors and wire manifold 
with all wires intact. 

5. Remove intake manifolds from cylinder blocks, 
leaving gaskets and nuts on the blocks. 

6. All models except model A. Remove cotter pins 
from magneto couplings. Cut sealing wires and take out 
cap screws holding magnetos to their bracket. Slide back 



44 



WRIGHT AERONAUTICAL ENGINES 




Lifting out carburetor 

coupling till the outer sleeve disengages with the gears 
and then lift off magnetos. 

For model A magneto removal see page 47. 

7. Take off magneto bracket by removing the nuts 
on the circular flange holding the bracket to the crank- 
case. The bracket can be loosened without breaking the 
gasket by gentle tapping with a rawhide hammer. Never 
attempt to pry off the bracket with a screwdriver. In 
the case of models E or I the scavenging oil pump should 
remain with the magneto bracket and be detached later. 

8. Remove water connections between water pump 
and cylinders. Leave gaskets and nuts on the blocks. 

9. When gun synchronizer attachment is fitted this 
should be removed at this stage, together with the bevel 
pinions which fit inside the casing at the crankcase end of 
the vertical shaft housing. 

10. Remove the four nuts which hold each of the 
vertical shaft gear housings to the crankcase. Loosen 
these housings by gentle tapping; slide them up the tubes 
which inclose the vertical shafts and replace the nuts on 
their studs. 

11. Remove camshaft covers. 

12. Remove the four nuts from each of the end cam- 
shaft bearings. When these are free remove the nuts 
from the center bearing and lift shaft and bearings off 
the block. Note that it is important to free the end bear- 
ings first so that camshaft can rise up level under the 
valve spring pressure as the nuts on the center bearing 
are removed. Note also that each of the nuts and studs 
of the twelve that hold the camshaft bearings to the cylin- 
der block are marked. This is because the cotter pin 
holes are drilled after the original assembly and if the 
nuts are not put back on their proper studs at reassembly 
there is great danger of straining the studs by trying to 



pull down a nut too tight in reaching 
the cotter pin hole. 

13. Detach connections between 
the oil pipes which are at the front 
end of the cylinder blocks and the 
crankcase. 

14. Remove cylinder holding 
down nuts leaving in place two nuts on 
each block. Tnese should be the 
uppermost nuts on cylinders one and 
three, that is the nuts nearest to the 
top of the crankcase. The special 
wrenches W A 52 or 92 are practically 
the only tools with which cylinder nuts 
can be removed easily. 

15. Having all the nuts off, except 
the two to each block just mentioned ; 
turn the crankshaft till the tongue and 
slot forming the connection between 
the upper vertical shaft and the lower 
shaft lies crosswise to the engine. 
This is to allow the cylinder block to 
be rocked to and fro to loosen it with- 
out risk of straining the vertical shaft. 

Then remove the last two nuts and partly lift off the cyl- 
inder block. In rocking it to break the joint with the 
crankcase very little force should be used. 

16. When the cylinder block is lifted a little way put 
in place the piston protector. This is shown on the next 
page. It is a copper tube as long as the cylinders and 
with either four or eight holes drilled in one side accord- 
ing to the model of the engine. A diameter of pipe about 
three-quarters of an inch is suitable. The holes are 
placed so that the pipe will slip over and so cover the 
ends of the lower cylinder holding down studs. Without 
this fixture, when the cylinder block is entirely removed, 
the pistons will fall against the lower studs with sufficient 
force to do damage. Even if care is taken to prevent this 
happening at the moment of cylinder removal, it is likely 
to happen afterwards and the time spent in making the 
fixture will be recovered in the overhaul of the first en- 
gine. Of course it is not essential to use copper pipe in 
precisely the way illustrated as long as the stud ends are 
covered. Another way used in some field shops is to cut 
short pieces of stout, small rubber hose and place them 
over the studs. 




Wrench for cylinder holding nuts 



WRIGHT AERONAUTICAL ENGINES 



4b 



17. Remove first cylinder block com- 
pletely, and repeat all operations for other 
block. Before removing second block do 
not forget to see that the tongue and 
slot in its vertical shaft are transverse to 
the engine. 

IS. Except for E-2 and H-3 models, 
all recent models have pistons in which 
the wrist pins are floating and are pre- 
vented from endwise movement by alumi- 
num caps which fit into the pistons. See 
cut on page 6. To remove these caps an 
8 mm. bolt is necessary. Screw this into 
the tapped hole in the cap about two 
direads deep and the cap can be pulled off. 
All caps and pistons are marked and must 
be put back together in accordance with 
the marks, so keep the caps together with 
each piston. 

Wrist pins have to be tapped out by 
using a drift. It is best to have two men 
for this job, one to drive and the other to 
hold the piston. If the job has to be 
done by one man he should hold the connecting rod as 
close up to the pistons as possible with the left hand 
and tap out the pin with the other. It is very impor- 
tant not to tap hard enough to put any side stress on 
the connecting rod, as the latter is easily sprung. 

Do not drive wrist pins right out, merely far enough 
to allow pistons to be removed. 




Use of copper tube to protect pistons from injury by cylinder studs 

If the work is done in a cold shop the pistons should 
be heated before attempting to drive out the wrist pins. 
For removal of older model pistons sec page _//. 

Second Stage 

This completes the first stage of the disassembly. The 
procedure up to this point covers the tearing down neces- 




Showing removal of water and oil pumps from Models H, H-2 and H-3. 
E-2 is disassembled in precisely the same manner 



Mode 



46 



WRIGHT AERONAUTICAL ENGINES 



BALL BEARING A55Y. 



THRUST BEARING A55Y. 



SUPPORT 



Copper or lead jaw 
plates on. vise 




Simple and secure support for crankshaft assembly 



sary for a minor overhaul where valve grinding and gen- 
eral inspection are the objects. The second stage of dis- 
assembly covers the taking apart of the crankcase. 

19. Remove the oil pressure gage hose connector 
from the side of the lower half of the crankcase. If not 
taken off now it is liable to be damaged in moving the 
case. 

20. On the top of the crankcase there are ten nuts all 
locked by sealing wires. These are the nuts of the long 
bolts which hold together the two halves of the crankcase. 
Leave the four at the front end and the two in the center, 
but remove the other four. 

21. Lift the crankcase out of the stand and lay it on 
its side. 

22. Remove crankcase flange nuts, bolts and washers 
from the upper side of the case. 

23. Remove oil and water pump assembly. 
Models H, H-2 and H- 3 . 

Detach external suction pipe at its front end flange 
connection with the crankcase. Remove nuts on pump 
base plate and lift off assembly. Take out strainer and 
oil pressure relief valve. 

Models A, E and I. 

Take off four nuts holding water pump bracket to 
crankcase. The water pump will then draw off and the 
inner member of the oil pump will follow it. As the oil 
pump shaft comes out grasp it firmly so that the pump 
vanes do not come out of their slot, as they may be dam- 
aged by falling. Directly the shaft is withdrawn tie a 
piece of wire round the vanes to hold them in position. 
Remove oil strainer and oil pressure relief valve. 

On Model E-2 after removing Pump Assembly the 
two stud bolt nuts at rear bearing inside of crank case 



must be removed. These can be reached through the 
pump opening. 

24. Turn crankcase over on its other side and remove 
flange bolts, nuts and washers as before, from the other 
side. 

25. Set the case back in its original position on the 
stand and remove remaining six nuts from the crankcase 
bolts. 

26. Place the crankshaft so that the throws are hori- 
zontal. If this is not done the plugs in the crank throws 
will catch on the main bearings and prevent the separa- 
tion of the upper from the lower half of the case. 

27. Lift the case at one end about three inches off 
the stand and let it fall sharply back. The shock will 



N J«A 





Removing oil pressure release 
valve from Model H engine 



break apart the upper and lower halves of the case and 
the upper half can then be lifted off by raising it from 
each end simultaneously and being careful to keep it 
level. 

28. Lift out the crankshaft and place it on a special 
stand as shown at the top of this page. 

This completes the major disassembly. 



DISASSEMBLING MODEL A 



THE procedure for tearing down model A is almost 
exactly the same as that for models E and I. It 
differs in the magneto removal and in the taking off 
of the pistons. 



Magneto Removal 

1. Remove nuts from flange studs holding housing at 
bottom of vertical shaft to crankcase. 

2. Cut locking wire on magneto holding down cap 
screws. 

3. Remove holding down cap screws. 

4. Lift up magneto and the housing, loosened in 
operation 1, together to clear dowels. Then draw back 
magneto, and pinion will slide ont of housing remaining 
with magneto. During this operation be careful not to ^ 
strain housing, which is rather delicate. 

Piston Removal 

1. Tnrn oil rings until the gap in the ring registers 
with the hole in which lies the head of the wrist pin lock 
screw cotter. 

2. Straighten ends of cotter very carefully, grasp them 
with the pliers and tap back the pliers with a hammer till 
the head of the cotter projects enough to be grasped and 
pulled ont. 

3. Remove wrist pin lock screw, using the special 
model A tool YV A 71. If this tool is not available a special 
socket wrench will have to be made. The screw has a 
square head and the socket requires a 7/32 in square hole. 

4. Drive out wrist pins by same method as for other 
models. 

Connecting Rods 

1. Remove the cotter pins and nuts from the four 
bolts of the bridged cap. 

2. Remove the cap by very gentle tapping on the arch. 
This cap binds very easily and is easily injured. 



3. Remove the cap screws from the inner rod and rod 
will be free. 

4. In lifting off rod be careful not to strike against the 
plugs which close the hole through the crankshaft, as the 
babbitt can easily be burred by them. 




Tilting engine stand in use, showing how operator should grasp 
engine in order to rock it over onto the side leg of stand 



CLEANING ENGINE PARTS 

Recommended Washing Equipment to Insure 
Absence of Dirt and Thereby Give Long Life to 



OWING to the close fits essential to an aviation 
engine, and to the very high bearing pressures 
extraordinary damage can be done by quite small 
amounts of dirt. Grit that would never be found in an 
automobile engine can easily be sufficient to heavily score 
bearings and pistons in an aviation motor. 

The use of compressed air for blowing out parts dry 
is not enough ; nor is it enough to wash them in a pail of 
more or less dirty gasoline. 

THE MORE SCRUPULOUSLY CLEAN THE 
PARTS AT ASSEMBLY THE LONGER THE 
ENGINE WILL RUN WITHOUT OVERHAUL. 

The best cleaning equipment consists of two tanks 
about four feet long, three wide and two deep. 

These tanks should be placed close together on a wood 
stand which will raise them a foot off the ground. Each 
tank should have a drain cock in the bottom. 

Inside each tank there should be a false bottom of 
wood slats raised about six inches from the actual bottom 
of the tank. The slats should be about an inch apart. 

On either side of the tanks should be a sloping table 
draining into the tank and above and behind the tanks a 
shelf or two of slat construction. 

Use of Equipment 

The tanks should be filled with gasoline or kerosene to 
within about eight inches of the top. One tank should be 
used for the washing of dirty parts coming from dis- 
assembly, the other for clean parts, inspected and ready 
for final re-assembly. 

Each part should be placed in the tank and left there 
soaking for at least five minutes. The false bottom sup- 
ports the part below the surface of the gasoline and any 
heavy dirt, such as particles of babbitt, will drop through 
the slats to the bottom of the tank where they can do no 
further harm. The operator requires several bristle 
brushes and a squirt gun. Parts like a crankcase should 
be first soaked for five minutes, then lifted up and rested 



upon two pieces of wood laid across the top of the tank. 
In this position the brushes should be used, the case 
sluiced and the squirt gun employed for forcing gasoline 
through bolt holes, etc. Then the case should have a 
second, shorter soaking before being lifted out to drain. 

A long soaking is advisable for crankcases, cylinder 
blocks and pistons. Shafts, gears and small parts gen- 
erally require much less. Frequent use of the squirt gun 
to clear all small holes is important. 

For cleaning out the oil holes inside the crankshaft 
the squirt gun is again used, but this operation calls for a 
helper who by covering the various holes with his fingers 
allows the operator to wash out one orifice at a time. 
This equipment should be situated in a building free from 
dust and with regard to fire risk it may be remarked that 
kerosene is practically as good as gasoline for cleaning. 

There should be drying racks in the building and 
parts should never be sent to re-assembly until they are 
thoroughly dry. A point worth remembering is that 
soaking is more effective on old, caked oil than scrubbing, 
and it is sometimes economical of labor to soak crank- 
cases or pistons for as long as half an hour. 

Owing to the opportunity for sediment to collect at 
the bottoms of the tanks, beneath the false floor, the 
kerosene or gasoline lasts a long time, as it only becomes 
unusable when it has taken up so much oil that its cutting 
properites have been lost. For this reason it is well to 
drain off all oil possible before washing. Where many, 
parts have to be cleansed the amount of time and of 
gasoline saved by this equipment is substantial and the 
cost of the installation is thus rapidly recovered. 

Experience has proved that cleaning parts of aviation 
engines to a degree that at first may appear ridiculous' is 
actually highly economical. The number of hours a motor 
will fly without trouble is largely controlled by the amount 
of dirt remaining in the oil passages when it is put 
together. The total life of bearings and pistons is simi- 
larly affected. 



OVERHAUL OF WRIGHT ENGINES 

Instructions for Disassembly of Detail Parts, 
Their Inspection, Repair and Reassembly 



WHERE reasonably frequent overhaul of Wright 
engines has to be made the use of the cylinder 
holding fixture illustrated on pages 50 and 51 is 
recommended strongly. A blue print of this fixture will 
be supplied on request to the company. 

This fixture holds one cylinder block at a time, so 
that it can be rotated on the pivots, and the lock pin holds 
it any way up that the operator requires it. It is com- 
posed of lumber, flat steel strip and two standard iron 
pipe flanges and can be made up with the simplest tools. 
It is adjustable to suit either the E or the H series of 
engines. 

Together with this stand four pieces of wood are 
required of a size and length which roughly fits the inside 
of the cylinder. One such piece is placed inside each 
bore and all four are held in place by a strip of flat stock 
cut to the length of the block and drilled so that it can 
be held in place by a bolt through each of the end cylinder 
flanges. These blocks of wood, held up in this way, 
support the valves and prevent them from lifting when 
the springs are held down for the removal or replacement 
of a tappet. 

Procedure on the cylinder block after its removal from 
the engine is as follows : 

1. Place block in holding fixture and attach wood 
blocks to hold up valves. 

2. Set block vertically with valves on top and attach 
valve lifting fixture. This is the fixture illustrated in 
use, in the cut on this page. It can easily be made up 
from this illustration or a blue print can be obtained from 
the company. The two end pieces of the frame of this 



fixture are held down by putting two nuts on the end 
studs of the camshaft bearing studs. It is necessary to 
make up a frame for the E series and another for the H 
series of motors, since although an adjustable frame 
could easily be devised it would hardly be worth while. 

3. Insert the short end of valve assembling lever 
(tool W A 15) below the back bar of the frame. Move 
the lever till the two pins slip through opposite notches in 
a tappet head. Then press down on the lever and the 
valve spring washer will be forced clear of the tappet. 

4. Unscrew the tappet. If this is more than finger 
tight use the socket wrench (tool W A 19). 

5. As the tappets are removed and valve springs and 
washers lifted off, be sure to place them in order on the 
bench from number one to number eight. 

6. Turn block over on its pivots and remove the blocks 
of wood holding up the valves. Remove valves one by 
one and immediately replace the washer and tappet 
belonging to each. Keep the valves in arranged order or 





Shows fixture for removing valves in use. The frame is held by the end 

camshaft bearing studs and the tappet washer depressed by the 

lever. The tappet can then be unscrewed by hand. 



Valve tappet lifting tool used for removing valves 



check to see that each is marked. Even 
when marked be careful not to get the 
valves from right and left hand cylin- 
der blocks confused. 

7. Using spark plug bushing 
wrench (tool W A 12) test each 
spark plug bushing for tightness. If 
any are found loose they should be 
removed and replaced, using a new 
copper ferrule gasket on the nose of 
the steel bushing. The use of a new 
gasket is very important, to tighten up 
a loosened bushing on an old gasket is 
very liable to leave a slight water leak. 

Spare spat 
out tupped a 



plug bushings are sent 
it tie undersize. After 



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52 



WRIGHT AERONAUTICAL ENGINES 




Spark plug bushing and ferrule 

putting in a new bushing an 18 mm. tap should be run 
through it. 

Cylinder block is now ready for inspection. 

Inspecting Cylinders 

After washing and drying (see instructions for clean- 
ing, page 48) cylinder blocks should be inspected for 
superficial defects such as cracks in the water jackets. 

It is important to observe the condition of the top sur- 
face on which the camshaft cover rests, as this must be 
quite smooth and flat. The bronze bushes into which the 
cover screws go sometimes loosen. See that they are all 
tight and level with or below the surface of the aluminum. 
If it is necessary to do any smoothing work the cover and 
block should be gone over together, using blue and scrap- 
ing high spots so as to get the best possible oil tight join 
between the two parts. 

Cylinder Sleeves 

These should be inspected internally for scores or 
scratches. Roughness due to a score should be removed 
with a half round Arkansas stone of fine grain. A deep 
scratch need not, in fact should not, be completely stoned 
out, as this is liable to distort the bore too much. If all 
rough or sharp edges are stoned out the score itself will 
do little harm provided, of course, that it is not too large. 

Inspect for roundness carefully. A cylinder sleeve 
which is much out of round will cause serious loss of 
power and heavy oil consumption. If over .006 out of 
round it is recommended the block be returned for re- 
sleeving. 

In case it is necessary to reject a cylinder sleeve for 
deep scores or for out of round the cylinder block zvith 
the camshaft cover in position must be returned to the 
Wright Aeronautical Corporation for the insertion of a 
new sleeve. New sleeves can be put in easily with the 
factory equipment, but without it the job is very difficult 
and uneconomical. The camshaft cover should be put 
back before shipping in order to protect the top surface 
of the block and to prevent the studs for the camshaft 



bearings from being injured. Outside of cylinder walls 
should be thoroughly slushed with a high grade slushing 
oil to prevent rust during shipment. 

In cases where a cylinder bore is scratched up a good 
deal by grit, but none of the scratches are deep, it is a 
good plan to lap with an old piston and new piston rings, 
using plenty of oil and a very fine abrasive, preferably 
crocus. Note particularly that before lapping a block of 
wood must be put in the cylinder thick enough to prevent 
the piston from striking the inwardly projecting nose of 
the spark plug bushing. A slight blow on this is almost 
certain to cause a water leak. 

Valve Seats 

The valve seats are usually glazed after an ordinary 
length of use and have a very hard skin. Using an old 
valve and coarse grinding compound this glaze should be 
broken, but never grind more than enough to break the 
glaze, the less grinding done the better. 

The glaze being broken, the seat should be reamed 
with tool W A 7. This tool consists of a handle and 
two cutters, each cutter being complete with its pilot fit- 
ting in the valve guide bushing. There are two cutters 
because the valve guides are reamed to different sizes and 
care must be used to see that the intake cutter is used for 
the intake valve and the exhaust cutter for the exhaust 
valve seat. The pilot of the exhaust valve cutter will not 
go into the intake valve guide, but the intake valve pilot 
will go in the exhaust guide. It is, however, so loose a fit 
that a true seat could be reamed only with great care. 

Good steady pressure is required on the handle of the 
seating tool, and the least possible amount of metal should 
be removed which will bring the seat smooth, as it is bad 
to cut away much. Too deep a reseating operation will 
"swallow" the head of the valve and so restrict the valve 
opening and cause excessive valve heating. 

It may be observed that the teeth on the seating cutters 
are not radial, but are set at two different angles. This is 
done because it enables a smooth seat to be cut more 
easily. Cutters should be kept very sharp and great care 
taken to wash off all grinding dust before using the cutter. 




Cylinder block with camshaft cover as it should be 
assembled if sent to factory for any kind of repair. 



WRIGHT AERONAUTICAL ENGINES 



53 



It should always be the desire to get a perfect scat with the 
cutter: the less grinding required afterwards the better. 

Valve Guides 

These should be tested with the guide plug gauges 
i^see tool list page 78). If these are loose more than 
.005 new guides are required. New guides are supplied 
by the factory bored to one size. To fit a new guide, 
remove the old one with a socket wrench, and screw in 
the new one as tight as possible with a socket wrench 
and a bar about a foot long. Remember that the thread 
is fine and is cut in aluminum, so do not use too much 
force. Make sure that the collar on the guide seats flat 
against the faced lug on the cylinder block. If it does 
not do so, try another new guide before doing any 
scraping. 

/;; fitting a new guide to a Model A for the first time 
it is necessary to do a small machine operation on the 
cylinder block. The cut shows, on the left, the design of 
the original Model A guide and cylinder and it will be 
seen that there is an upwardly projecting lug on the 
cylinder casting into which part of the valve guide slides, 
the guide not having a collar. On the right hand side of 
the illustration is shown the form of guide supplied for 
replacement — identical with the Model £ guide. It is 
therefore necessary to machine off the lug from the 
cylinder block to suit the new design of guide. The 
illustration gives all necessary dimensions for this opera- 
tion. 

After inserting a new guide it must be reamed to size, 
using the expanding reamer and the intake and exhaust 
valve plug gauges ( see tool lists for E and H series, 
page 78). 

The new guide being reamed the valve seat must be 
trued with the reseating cutter, as it is practically impos- 
sible for the old seat to be true with the new guide. 

Vertical Shaft Bearing 

In an ordinary overhaul it is not necessary to remove 
the upper vertical shaft from the cylinder block, provided 
care is taken not to damage it during handling, especially 
during washing. 

To remove it the tubular casing is taken off by un- 
screwing it at the top end 
and then driving up the bear- 
ing with a block of wood 
and a hammer as shown in the 
cut on page 55. Be sure to 
tag the shaft with its bearing 
and the tubular casing so that 
it is reassembled on the same 
cylinder block. 

Inspect the vertical shaft 

for end and side clearance in 

Correct valve seating accordance with the clearance 

.. A ,. , , . chart, page 54. Also examine 

A must not be less than 

1/64" and should be teeth of gear and reject gear 

1/32" if there is any sign of rough- 







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When fitting new valve guides to a Model A cylinder, the lug 
shown on left must be removed as shown on right 

ness on the tooth surfaces. In case it is necessary to 
fit a new vertical shaft bushing in the cylinder block 
one particular precaution should be taken, which is as 
follows : The tubular housing screws on the lower end of 
the bushing thus holding it in place, and there is a spring 
wire lock ring. If a new bushing or a new housing is 
fitted it will generally be necessary to drill a new hole for 
the turned in end of the lock ring. This hole must not be 
drilled right through, as, if it is it will cause an oil leak 
that is hard to find, but large enough to be a serious 
nuisance. 

Valve Inspection and Seating 

Various steels have been used for valves and some of 
them are only suitable for intake valve work; therefore, 
care must always be taken to observe the marking on the 
head of a valve, which shows whether it is an intake or 
an exhaust valve. 

Valves after removal and cleaning should be chucked 
and examined for warping, but a valve should not be re- 
jected for warp which can be corrected while regrinding 
the valve face, as an old valve if in generally good con- 
dition will usually retain its shape in service better than 
a new one. 

Always regrind the valves on a universal grinder or at 
least with the valve chucked by its stem. Never attempt 
to grind out pits or warp in the cylinder, as to do so will 
cause excessive wear on the cylinder seat and also give a 
poor seating. Remember that the ideally finished valve 
and cylinder seat require no grinding together and that 
the less grinding of valve in cylinder the better. 

After setting up the grinding rig to reface the valves, 
do one and then try it in the cylinder. Use a little of the 
finest grade of grinding material and grind lightly without 
pounding for two or three minutes, not more. 

This should show a seat of good width in accordance 
with the sketch on this page and should make the valve 
gasoline tight. In fact, five minutes at most should be 
enough. 

If the first valve tried cannot be seated so easily, then 
change the setting of the grinding wheel so as to make the 
valve seat angle suit that of the cylinder better. Or pos- 
sibly the trouble may be due to blunt reseating cutters, or 
to use of the wrong pilots in reseating. 

Remember that the perfect seat on the exhaust valve 
should be not less than 3 e>2 inch wide and that it should 



WRIGHT AERONAUTICAL ENGINES 




WRIGHT AERONAUTICAL ENGINES 



55 



be as little wider than this as is possible, so that when the 
engine is overhauled, there will be the maximum allowance 
for refacing". A very narrow seat is more easily made 
tight but warps easily. A very broad seat carries away 
heat better, but cuts down the allowance for refacing and 
carbonizes on the face more easily. A valve should be 
ground as little as possible to obtain a good seat. Much 
grinding never makes a proper set. 

To spend a good deal of time in keeping the reseating 
cutters up to the mark, in properly chucking old valves 
for grinding, and thereby cutting down the conventional 
''grinding in" period, is the truest economy. The number 
of hours an engine will fly is directly dependent upon tlvt 
perfection of the valve seat. Valve heads must not be 
"swallowed" in the cvlinder seat, but a clearance of about 
1 64 inch is enough. If the seat in the cvlinder has been 
reamed out too large it is possible to save the sleeve by 
making a cutter with a thirty-degree angle and with this 
removing the corner of the seat so countersinking the 
actual valve seat till the head of the valve projects the 
necessary 1/64 inch. 

Valve stems should be gauged and checked against 
the respective guides. If the intake valve stems are as 
much as 0.005 loose above called for dimensions, either 
valve or guide, or both, should be changed. This seems 
a small amount, but the unusual diameter of the stem 
means that a small excess clearance can cause quite a 
noticeable leakage of oil down the guide, quickly fouling 
the valve Exhaust valves are not quite so delicate since 
oil leaking down will burn off if the quantity is not too 
great. 

Finally, remember that valves are the heart and lungs 
of an engine; if the} are not perfect the engine as a 
whole cannot give any sort of satisfaction. 

Valve Tappets 

Reject valve and tappet when the tappet is a very easy 
fit on the threads, as in such case the threads are almost 
certainly damaged. 

Reject tappet when it shows marks indicating that it 
has been revolving a great deal. 

Stone out scratches on tappets otherwise in good con- 
dition, and stone tappet heads a little. The case is 
0.020 thick or more, so considerable stoning can be done. 

Valve spring washers sometimes strike against the 
top ends of the valve guides and are damaged. Examine 
for this and replace washers if necessary. If new guides 
are fitted check height of guides to make sure that there 
is plenty of clearance under the washer when the valve 
is lifted. 

Check valve springs for strength in accordance with 
table, page 76. 

Replacing Valves 

After reseating valves and checking all points just 
covered, all parts must be again washed and dried before 




Driving out upper vertical shaft bearing, using block of wood 
faced with fiber 

assembly. To assemble, place all valves in position with 
cylinder block in holding fixture. Insert blocks of wood 
described on page 49 to hold valves in place and turn 
over cylinders. 

Attach the valve lifting" fixture illustrated on page 
49, and replace tappets by reversing the method used 
for their removal. Have a gauge made from sheet steel 
which will roughly check the height of the tappet above 
the top face of the cylinder block which should be §i in. 
for all engines. Screw down the tappet till it is a trifle 
below the gauge. 

Be sure that intake valves and exhaust valves are not 
mixed and that all valves go in their proper places. It is 
worth while to inspect this as a single error will cause the 
rapid burning out of a valve. 

Camshaft Inspection 

Unless there has been failure of the oil supply the 
camshaft bearings rarely require renewal. If they are 
damaged it is highly desirable to replace all three bearings, 
as they must be line reamed after bolting down in place. 
One new bearing can be fitted, of course, but only by 
much scraping and use of the camshaft bearing aligning 
bar (W. A. 2). 

In fitting new bearings new cotter pin holes must be 
drilled in the studs or— which is better practice- -the nuts 
riled down when the difference is not too great. The 



:>6 



WRIGHT AERONAUTICAL ENGINES 



rs- 



004 ' Mm. 

.0/2' loose des> W 

.020' Ma x. 



Plug must be square *•.,,, - ■ 
Cylinder sfecfe and edges 
rounded 

Tongue clearance Zapping 
f if desired .00! "Loose Max.^ 



*b= 




IL_. , \,^ ~ 




.00!" Loose desired^ 
.002" Max. 




.Tongue c/eaian^y 

1 0!S"Min. 
020" Loose desit id 
.025" Max 

Pin m shaft .000' h .002" Loos- 
Peon snoff sfighf/y to secure pu> 

.002 "Mm. 
!. 003' Loose desired 
' .004 "Max 

.001" Mm. 

1.0025 Loose desired 
I 004' 'Max 



^ 



-FifoFkegmshoFf 
00025" Tight desired 
COOS' TightMox 
Fit of keg in geor 

.OOOS'Mln. 

.0007" Loose desired 

.OOl'Mox. 

0OOS"Min. 
.001" Loose desired 
.006 "Max 
Shrink fit 
'osi he tight on snarl 
~ .001 "Mm. 

.002" Loose desired 
.003" Max. 

^OOOS "Mir,. 

.00/ " L oose desired 

.OOIS"Max. 

"t/ut mas/ shou/der here 
~.006" Tight 

Press Fit desired 

.00! ~ Loose Max. 
* End clearance 

.COS "Min. 

.010 "Loose desired 
.JII5" Max. 

5" Min. push Fitdesireo 

-.039" Mm. 

£42 "Loose desired 
045"Max. 
-.033" Min. 
£36" Loose desired 
.039" Max 

-.020 "Mm. 

.032" Loose desired 

.035" Max. 
-S/o/ m rings 

.008" LooseMm 

.012" Loose Max. 

-.020" Min. 
032 "desired 
.035" Max. 



..00/ Min. 

.00/5" Loose desired 

002" Max 



-Pislon shir/ 
Clearance 
0153 Min. 

Loose desired 
.0205" Max. 



^^ 



Fits, clearances and tolerances for parts 
shown of Models H, H-2 and H-3 



^: 




.002"Mm. 

005 "Loose desired 

008 "Max 



4 



WRIGHT AERONAUTICAL ENGINES 



57 



camshaft bearing studs are slender and the nuts must not 
be pulled down too tight or the studs will be strained dan- 
gerously. Before fitting a new bearing try a nut on an 
old one and so get the proper degree of tightness. 

For reaming new bearings the special reamer (W. A. 
1 ) fits both E and H series engines, as does the camshaft 
bearing aligning bar (W. A. 2). Before reaming make 
sure that the bearings are bolted down securely. If on 
trying the camshaft in the new bearings it appears tight, 
again see to it that the bearings are firmly bolted down, 
because if one is slightly loose it may feel tight on the 
shaft and yet be free when pulled down. 

Follow the clearance chart on this page carefully in 
fitting new bearings, especially as regards end clearances. 



c 



am 



aces 



These should be looked over for scratches and may be 
polished with a fine stone. Scratches of any depth will 
inevitably score the tappets. 

Clean out the inside of the camshaft very thoroughly 
indeed and, if it is to lie for a time before reassembly, 
plug all oil holes so that no dust will get inside. 

When remounting the camshaft check the backlash 
and clearances of the driving bevel gears and keep them 
to the amounts specified in the clearance charts. When 
testing backlash be sure to try it all around the gears and 
not only at one point. It is important that the backlash 



should not be too great, but still more important that 
there should be no really tight spots. 

Crankshaft and Connecting Rods 

First, after removing all connecting rods and washing 
the shaft, test on vee blocks for straightness. A shaft 
should never be used that is more than 0.003 out on the 
taper end. If not more than 0.005 out straightening by 
springing is possible but is bad practice, as a shaft so 
straightened will seldom stay straight in service. 

These amounts may seem very small, but experience 
has shown that a shaft that is not nearly perfect is really 
dangerous. Second, examine bearings for scores and if 
necessary polish with a stone and crocus powder used 
on a rawhide strap in the conventional way. Before ston- 
ing or using crocus be sure all oil holes are plugged with 
tallow, as fine grit inside the shaft is hard to clean out 
completely. A shaft is usually considered to be worn 
out and fit for rejection when the bearings are 0.005 
undersize. 

Third, examine the taper for signs of movement be- 
tween shaft and propeller hub. If there are any signs of 
picking up, stone these out and then remove the key. Lap 
the hub, using fine grinding compound, and continue lap- 
ping till the very best possible contact is obtained. Great 
care must be taken that the hub does not ride on the top 
of the key. The key should be replaced if damaged, 



.002 " Tight 
Tapping fit desired 
.004" Loose 
■f////// ZZZZ Z TZZi 
.00 2 "Min. 

.003" Loose desired 
.004 " Max.. 



Spin or pean disc 
in place 



Hole in camshaft must 
register with hole in 
bearing. 



As near Oil tight 
practical 

Gasket 



Hole in bearing mu 
register with hole 
in cylinder jacket 



3roi 




Min. end clearance .010- 



' Flange must register 
in cylinder jacket. 



^Oil tight joint 



Clearances, fits and tolerances for all models 



Camshaft bearings should 
be line reamed 



002" Min. 

003" Loose desired 

004" Max. 

/////i/iii/iil 





Oil Moles in 

/leading side 

of cam 



Tapping Fit 
.001" desired Loose 
002" Loose Max. 

.000" 

.001 5" Tight desired 

003" Tight Max. 



.000 "to .001 "clearance 
.000" to .004" Clearance 




cross section of camshaft 
b'r'g. 



58 



WRIGHT AERONAUTICAL ENGINES 



should be tight in the shaft, and the hub should be a good 
sliding fit. Hubs which are not perfectly bedded down 
to the taper end of the shaft will always "work'' in ser- 
vice and this causes roughness to develop which may 
easily lock the two parts so tightly together that they will 
be impossible to separate. 

Observe that crankshafts are match marked to their 
hubs and to their connecting rods. The shaft, hub and 
connecting rods make an assembly which is not inter- 
changeable in detail after fitting. 

Thrust Bearing 

The condition of this bearing is important, as it carries 
a very heavy load. To remove it take off the lock spring 
and unscrew the nut with wrench (W. A. 9). Look for 
flat spots on the balls and for marks in the races ; also for 
eccentricity on the ball path. If in any doubt about a 
thrust bearing renew it. 

Try the bearing in both upper and lower crankcase 
halves. The bearing with its washers should be so tight 
in the case that it can just be turned by hand. If it is free 
so that it turns very easily a new washer must be fitted. 
In putting in a new washer, first make sure that it beds 
down against the back of the race so that a 0.0015 feeler 
cannot be inserted between them at any point ; then grind 
or lap down the washer till the proper fit in the case is 
obtained. 

The spacer collar on the crankshaft should be of such 
a length that, when the nut is dead tight, the bearing will 



make not more than one or two revolutions when spun 
sharply by hand. If it is more free than this grind down 
the spacer. 

Because the thrust on the crankshaft is always in one 
direction (the propeller pulls the shaft forward all the 
time) wear on the thrust bearing always allows the shaft 
to move forward relative to the crankcase. For this 
reason in fitting thrust bearing washers on A, I and E, the 
rear washer should be thinner than the front one, so that 
the clearance between the crankshaft webs and the main 
bearing flanges will be greater on the forward side than 
on the rear side. Wear then causes the shaft to work 
tozvards the central position. Models E-2, H, H-2 and 
H-3 have a single washer at rear end. 

Next examine the ball bearing at the rear end of the 
shaft, but do not remove it unless it has more than 0.003 
in vertical play, or shows signs of damage. 

If it has to come off, a special puller is necessary 
owing to the small clearance behind it. Tool W. A. 6 is 
made specially for this job, but any puller of requisite 
span can be used by grinding down the ends till they will 
slip behind the bearing. The bearing should be a light 
drive fit on the crankshaft and if a new bearing is tight 
the shaft should be lapped down till the proper fit is 
obtained. The fit of the old bearing should be used as a 
guide for proper tightness. 

The crankshaft bevel pinion should be examined for 
wear and replaced if the teeth are not in really good con- 




0005 u Min. 

0015" Loose desired 

.003" Ma K. 

\>005" Loose Max. 
Bearings must fit 

WIS" Min. 

■002" Loose desired 
0025" Man. 



Large Diameter 
.003" Loose desired 
.006" Max. 
Smalt Diameter 
006"Min 

.012" Loose desired 
.022" Max. 
Spline clearance 
.001" Loose Min. 
.004" Max. 
At least two splines must 
touch and drive. 



Shaft and Key 
Side clearance 
.002 " tight 
Tapping Fit desired 
OOOS "Loose max. 
Hub and Keu 
.001" Min. 

.002" Loose desired 
.004" Max. 
Key top clearance 
.0041 Min. 

.010" Loose desired 
016" Max.. 



Front end fits and tolerances for all models 



WRIGHT AERONAUTICAL ENGINES 



59 



dition, as from this pinion all the supplementary shafts 
derive their drive. 

When a new pinion is fitted its mesh, with all the 
shafts it drives, must be checked against the clearances 
shown in the charts. The charts for models E and H 
are on pages 59 and 60 respectively. Adjustment of 
depth of mesh is obtained by lapping down the spacer 
washer behind the crankshaft pinion. 

Connecting Rods 

Connecting rods of the marine type as used on all the 
engines except Model A are easy to fit by conventional 
methods. If the babbitt inside the bronze box is much 
worn it can be replaced by conventional methods. Re- 
member that in fitting the bronze box to the crankshaft 
the two bronze halves cannot be filed off so as to brinsr 



them closer together, as this would destroy the circularity 
of the outside on which the outer connecting rod works. 

The inner babbit should be scraped to an 80 per cent, 
bearing and the babbitt must be renewed if the clearance 
between the crankpin and the bearing exceeds 0.006. On 
the other hand, a new bearing must not be fitted tight. 
The chart gives correct clearances and a rough test is 
that the rod, when the bolts are drawn tight and when 
oiled, should drop of its own weight, but should not 
oscillate pendulum fashion. In drawing up the bolts these 
should not be too tight, as it is possible to spring the box 
and strain the bolts. 

The outer connecting rod and its cap are ground to 
size and cannot be tightened. If there is excessive wear 
the only possible thing to do is to renew the bronze box. 
In fitting' a new bronze box to an outer rod the bronze 



dolt hofe must be a . 
reamed fit. 
Max. clearance 
.0005- 



All bearings must 
fit on diameters 
.0005" Loose Max.. 



.0015' loose des 
.003 'Mox- 

Beonngs must not touch" 
fillets on crankpin. 

008 'Mm. 

009' Loose desired^ 

310" Mar.. 

End clearance" 

.006' Min. 

DOT Loose desired 

DOS' Man. 



.0015" Mm.. 

Ml' Loose desired 

.0025'Mox. 



OOl'Min. 

OZS" Loose desired- Large diani of splines 



^.001 Mm 

.0025 'Loose desired 
0035"Max. 



Clearance chart, giving all fits 
and tolerances for Models E and I 
for parts shown. 



.002' Min. 

.0035 "Loose desired 

.005 "Max. 

Between gear tooth an J 

body. 




NOTE — Model H oil pump 
tolerances may be used for 
Model E-2. See page 60. 



001' 'Min. 

.003" Loose desired- 

.005' Max. 



.0005" Tight Mm. 
.002" Tight desired 
Drive fit 



-.0003" Tight Mm. 
.003" Tight desired 
Drive fit 
Ream & Face af assembly 

~~Approx . clearance ■ 030 " 

~.0OO5" Tight Mm. 
.001 "desired L oose 
.0025 Max. Loose 
Approx clearance .040' 



End play of shaft 

0O?'Mm. 

10' Loose desired 

.01 B' Max. 



60 



WRIGHT AERONAUTICAL ENGINES 



should be scrapped or lapped to the rod, not the other way 
around. A very fine flat file may be used on the bronze 
and in the hands of a skilful mechanic an excellent bear- 
ing obtained. 

In fitting a new bronze box great care must be taken 
to maintain proper alignment. Scrape the box where the 
feet of the divided rod attach to it to get good contact and 
test for alignment by putting a bar 6 inches long through 
the wrist pin bushing. Rods must not be more than 0.002 
inch out when tested on the ends of this bar ; that is to say, 
not more than 0.002 inch out measuring 3 inches distant 
from the center line of the rod. 

See that bearing clearances inside and outside the 
bronze box are between 0.003 and 0.005 and that end 
clearances of bronze on crankpin are between 0.014 and 
0.018. End clearances of outer rod on bronze should be 
from 0.007 to 0.009 inch. It is desirable to burnish the 
babbitt after scraping. 



The proper wrist pin clearance is not more than 0.005 
and if this is exceeded a new wrist pin bushing should be 
put in. 

Special reamers are made for E and H series engines. 
After fitting a new wrist pin bushing check the rod for 
alignment as just described when speaking of fitting new 
bronze boxes. 

Type A Rods 

Rods from a Model A engine should be inspected for 
condition of the babbitt. Slight cracks will do no harm, 
but if there is much sign of babbitt breaking away from 
tile rod it must be sent to the Wright Aeronautical Com- 
pany for rebabbitting. 

Owing to the very heavy pressures in these bearings it 
is impossible to rebabbitt these rods without elaborate 
equipment, all the various heats having to be controlled 
by pyrometer. The job of rebabbitting looks easy and it 



Same for outer bolt 



001 loose Mo*. 
Reamed fit 



.00 IS' Mm 
001' Loose desired 
.002 5- Max 



oormin. 

012 'Loose desired^ 
SIC Ma* 



OOlS'Min 

O02' Loose desired. 

.0025' Max. 



UOOS'Min. 
0015' loose des , 
003' Mai 



itring musfhold 
Screen ring fight 
against shoulder^ 



XZZZZZZ2 



00/ 'Mm 

£08' Loose des/red 

O/f'Max 




0005' Min. 
00/ "Loose des/red 
002" Max. 
002' Min. 

005" Loose desired 
OOf Max 
■005' Min. 
007" Loose desired 
009' Max. 
■Ball clearance 
0016' Min. 
004' Loose desired 
OOf Max. 
0005' Loose Max. 
Tapping fit desired 
■0005 L oose desired 
.001' Ma 'x. 

Bearing end clearance 
.0/0' Loose desired 
' Spline Side clearance 
001 Mm. 

0015" Loose desired 
0025" Max 
Small diameter 
.001 'Min. 

0015' Loose desired 
.002" Max. 
Large diameter 
.005 "Min. 

.018 'L oose desired 
j03i' Max. 



'0005" Loose desired 

001 'Max. 
- 001' Tight desired 

002' Tight Max. 
^[nd clearance 

005'Min. 

OI0" Loose desired 

0/5' Max. 
-.OOJ'tdin. 

008' loose desired 

.013" Max. 
~.00OS"Mm. 

00/5 'Tight desired 

00 i 'Max. 
~00l 'Mm. 

.002" Loose desired 
-^-003' Max. 
"~t0OO" 

00/5' Tight desired 
^003' Max. 

.00/ 'Loose des/recr 

002'Max. 
"004'Min. 

007 "I oose desired 

0/0' Max 



002" Mm. 

003 "Loose desired 

006 'Max 



Joints moy be shellaced* 
do not use gaskets 



Fits, clearances and tolerances for parts shown of Models H and H-2 ; also for H-3 with exception of magneto bracket 



WRIGHT AERONAUTICAL ENGINES 




Tapping Fit 
when cold 



Tongue c/eorance 
Tapping fit desired 
.001 ' Loose Max.. " 
Plug Diam. 
Tapping fit desired - 
.002" Loose 



Fits for piston pin of all engines and cap fits 
for Model H design 

is easy to rebabbitt a Model A rod which will appear 
perfect. However, it has been proved again and again 
that rods rebabbitted without factory equipment are un- 
reliable. There is no known method of testing a rod 
which will show how perfectly the babbitt is stuck to the 
steel, and if it is not in chemical contact all over, large 
pieces of babbitt will crack off in service. In fitting a 
rebabbitted rod the bearing clearances inside and outside 
should be not less than 0.0015 and not more than 0.005. 
End clearance on the inner rod should be from 0.008 to 
0.012, and on the onter rod the same amount. Alignment 
of rod after fitting should be tested as described in deal- 
ing with the marine type of rods. 

NOTE THAT ALL CONNECTING RODS ARE 
NUMBERED AND MUST BE REPLACED ON 
THEIR PROPER CRANK PINS. THAT CONNECT- 
ING ROD BOLTS ARE LIKEWISE NUMBERED 
AND MUST BE KEPT IN PLACE. 

Pistons 

Pistons should be examined for wear by checking the 
skirt diameter. Pistons may be used again which have a 
clearance of abont 0.008 more than the chart clearance, 
which is the ideal, but should be discarded when worn 
more than this as otherwise there is danger of excessive 
oil consumption. Scores sometimes call for the discard- 
ing of a piston. Slight scores may be stoned out and a 
deep score may be smoothed with the stone without trying 
completely to remove it. If the ring grooves are not- 
damaged a score is not likely to be serious. 

The wrist pin must be a good fit in the piston bosses. 
It must not be possible to insert the pin by hand alone. If 
it can be pushed into place in a cold piston it will be so 
loose under working temperatures as to be unsafe. A 
wrist pin which shows more than 0.002 wear should be 
replaced and the piston replaced also if it is not a good 
tight fit on the new wrist pin. 

The fit of the rings in the grooves is highly important. 
There should never be more than 0.003 side play which 
can easily be checked with a thickness gage and the end 



clearance at the ring joint should not exceed 0.025. Rings 
should be examined for wear on the face and discarded if 
there are signs of much leakage. 

Fitting New Rings 

When new piston rings have been installed the engine 
should be run in under its own power very carefully. The 
speed and load should be gradually increased, taking 3 
hours to reach the full load. Neglecting this will cause 
considerable loss of power. In fitting new rings the side 
clearance should be kept carefully to the limits shown 
on the clearance chart, and the end clearance should be 
held between 0.008 and 0.012. 

Oil scraper rings should be a tighter fit in the groove 
than the compression rings having a side clearance of 
0.002 and an end clearance not exceeding" 0.015 as an 
absolute maximum. 

Magneto Assembly 

It is seldom necessary to remove the magneto drive 
shafts or their bearings from the magneto bracket. After 
washing these parts should be given an inspection for acci- 
dental damage to bearings or gears due to particles of grit 
in the oil and for general wear. 

Before replacing a magneto bracket assembly the face 
of the flange and the corresponding face on the crankcase 
should be looked over for burrs or scratches which might 
cause oil leakage. 

In the event of its being necessary to replace any 
gears the clearances and backlash should be checked 
against the chart making sure that backlash is checked all 
round the gears and not only at one point. 



," 




Checking side clearance on piston rings 



62 



WRIGHT AERONAUTICAL ENGINES 



Oil Pump Assembly 

In the case of models E-2, H, H-2 and H-3 the oil and 
water pumps can be removed from the crankcase as a 
unit, or the water pump may be detached first. It is 
always desirable to open up the water pump for inspection, 
as there is possibility of corrosion. Similarly the oil 
pumps should be examined for wear or damage due to 
grit. 

It must be remembered that the two halves of the oil 
pump body are lapped together and have no gasket. 
Therefore great care must be taken not to scratch the sur- 
faces at the joint and in reassembling all parts must be 
perfectly clean and free from dust. The only parts of the 
oil pump assembly really liable to normal wear are the 
central drive shaft bushings of which there is one to each 
pump of the three in the assembly. If there is any suspi- 
cion of undue looseness the clearance should be checked 
against the chart and replacements made if necessary. 

The water pump is subject to wear on the shaft and 
on the babbitt shaft bushing. This should be checked and 
also the clearances between the rotor and the pump body, 
which should be within the limits shown in the chart on 
this page. Examine carefully for cracks or corrosion. 

Model E and I Pumps 

The vane type oil pump is more liable to wear and 
damage than the gear pumps of the later models and 
should, therefore, be examined more carefully. The oil 
pump body should be checked for looseness in the crank- 
case and for scratches on the inner surface. If there has 
been much internal cutting by grit a new pump body 
should be obtained. 




The vanes should be examined for scratches and for 
wear. Slight damage may be removed with a very fine 
file. In fitting new vanes the greatest care must be taken 
to insure that they work through the slot in the shaft 
quite smoothly without shake. The two springs which 



Tola I side clearance 
.001" M in. 
.004" desired 
007" Max 



Shaft with side of 
body 

.0005" Mm. 
.0015" desired 
.003" Max. 

N R1 i — i 

.001 Loose desired \ S * n 

.002" Max. IN ^ 



End Clearance 
.002" M in. 
.006 "desired 
.010" Max. 



001 Mm. 

.0015" Loose desired 
.006" desired 
.010" Max 



£04 Mm. 
DOT desired 
,010' Max. 




End Clearance 
Vanes in b 
.001 "Min. 
.002" desired 
.003" Max. 



End Clearance 

in Shaft 

.OOl'Mm. 

.004' Loose desired 

.007' Max. 



Oil pump and release valve fits for Models E and I 



.0005" Loose desired 
.001" Max. 



End clearance Total f~\ 
of assembly 
.004' Min. 
.008" desired 



Key Top Clearance 

002' C/earonce 

O08 " Clearance desired 

.0/4" Clearance 

Side clearance in cooolii 

S)0l "Loose desired 

J002' Max 



Tapping Fit' 
002" Max. 




0002' Mm Loose 
■001" desired 
00Z" Max. Loose 



0005" Tight Min. 
.0015" Tight desired 
0025' Tiaht Max. 



Fits and tolerances for magneto drive parts, Models E. I, H and H-2 



WRIGHT AERONAUTICAL ENGINES 



63 



separate the vanes should have approximately the same 
degree of tension. The efficiency of this type of pump is 
very good if the fitting is a first-class job but it is essen- 
tial that the clearances given in the chart are not exceeded. 
It is well worth while to give considerable time to the fit- 
ting of any new parts. It must not be forgotten that the 
end clearance of the vanes in the pump body is very 
important. 

No special instructions are required for the inspection 
of the gear type suction pump at the back of the magneto 
bracket on Models E and I. 

Oil screens and release valves should always be re- 
moved from the crankcase, cleaned and examined. The 
oil release valves occasionally require grinding in with 
fine abrasive, but this should only be done if there is 
obvious pitting or wear. 

Crankcase 

The upper half of the case requires the customary 
inspection for accidental damage and for condition of the 
cylinder holding down studs. It is not usually necessary 
to remove the lower vertical shafts, as they can readily 
be examined for condition of the bevel pinions and for 
fit in their bearings. Should any replacement be made, 
however, care should be taken to adhere to the clearances 
given in the chart, especially for the end play. 

The condition of the thrust bearing grooves in both 
halves should be examined for wear due to the thrust 
washer having turned in the case. Instructions as to the 
proper fit bteween the bearing and the case have been 
given on page 58 under the heading "Thrust Bearing.'' 

The seating of the ball bearing at the rear end should 
be examined for similar wear. It is almost sure to show 
some signs of the outside race having moved, but it is 
unlikely that the wear will be important unless there was 
a broken ball in the bearing. 

In the lower half are all the oil connections, the pres- 
sure release valve and the oil screen. The condition of 
the threads, surfaces, etc., should be inspected with a view 
to detecting possible oil leaks. The connection for the 



Diameter 

0038 ' Mm. 

.006" Loose desired 

.0061" Max 



.OO/'Min. 

.002 "loose desired 
.003" Max 



Nut must be tight enough to 
prevent leakage but not so 
tight as to interfere with 
shaft turning freetu. 




Square fit 
,001'Min. 

O03" loose desired 
XK>5" Max. 



.0005' Tight Mm 
003" Tight desired 



.000 S Mm 

.001" Loose desired 

00 IS" Ma*. 



0003 Mm 

.001' Loose desired 

.0025" Max 



End play of shaft 
.002" Mi n 

.010" loose desired 
01 S" Max 



Fits and tolerances for water pump of all models 

hose leading to the oil pressure gauge is rather liable to 
accidental damage, so the thread here should be given 
special attention. 

If any lapped surfaces are scratched they must be 
redressed with extreme care, as a quite slight degree of 
damage may cause a serious oil leak. 

Main Bearings 

Under usual circumstances the main crankshaft bear- 
ings will be in good condition and require only a little 
touching up and burnishing. Their clearance on the 
crankshaft should be checked, and renewal is necessary 
if this exceeds 0.006. Slight cracks in the babbitt will do 
no harm provided there are no large pieces. 

In fitting new bearings considerable time has to be 
given in scraping the outside of the bushes to the crank- 




Adjusting Model H 
water pump gland 




Adjusting Model E water 
pump gland 



64 



WRIGHT AERONAUTICAL ENGINES 




.004" Mm. 

.007" Loose desired 

.010" Max. 

Oil release valve fits 
all models except A 



case, because the oil is fed 
through grooves in the alumi- 

^ \ M mA num tnat enc i rc ' e tne bronze 

boxes, so that if the bronze 
does not bed down true and 
if the flanges do not bear 
against the crankcase bosses, 
there will be serious leakage. 
The halves of the bronze 
boxes must be perfectly flush 
with the aluminum. In fitting 
new bearings to the crank- 
shaft much labor is saved by 
using the expanding reamer 
which forms one of the spe- 
cial tools. Particular attention is called to the desirability 
of keeping closely to the clearances designated on the 
charts. These will give a fit that will appear distinctly 
loose to a mechanic who is a good hand at bearing fitting 
on other types of engines. It is highly uneconomical to 
fit new bearings entirely by hand as, while the special 
reamer is a somewhat expensive tool, the time saving 
consequent upon its use amounts to many hours on each 
occasion. 

Before reassembling the crankcase finally the long 
studs which hold the halves together should be examined 
for stretch. Sometimes these have been known to elon- 
gate so that when the blind nuts are drawn down they 
bottom, instead of bearing against the case. 

After assembling the crankshaft and putting the case 
together, it is advisable to attach the magneto bracket and 
then again check over the meshing of all the gears to 
make sure that there are no tight spots. 



Small Parts 

After tightening down all the main crankcase bolts, 
assemble the oil and water pumps, the release valve, oil 
screen and all crankcase attachments with the exception 
of the nozzle for the pressure gauge hose, which should 
be the very last part to be attached. 

Pistons 

Make a final check over the pistons to see that the 
proper equipment of right and left hand slotted rings has 
been used, and that the oil scraper rings have the bevel 
side uppermost. Warm the pistons till they can just be 
held in the hand, but only just, and then drive in the wrist 
pins. 

In the case of pistons which have the aluminum caps 
to retain the wrist pins with tongues slotted into the pis- 
tons, it was stated in the disassembly instructions that 
these caps should be kept with the pistons to which they 
belong. They are match marked and if mixed should be 
sorted out. See that they tap down snugly into position 
and are neither too tight nor too loose. 

E Piston Warning 

The only precaution to be observed with Model E 
and I pistons having the central ring retaining the wrist 
pin is to see that the ends of the wrist pins are rounded 
off. If they are sharp they may cut the retaining ring. 

Check the placing of the slots in the compression rings 
to make sure they are properly spaced and then coat the 
pistons with a good thick cylinder oil. 



Reassembly 

In a general sense the reassembly pro- 
cedure is the reverse of the tearing down 
and it will therefore not be described in 
complete detail. However, there are sev- 
eral special points of importance. Assem- 
bly must take place in a building free 
from dust and all parts must be as clean 
as they can be made. 

Crankshaft and Crankcase 

After mounting the connecting rods 
check for alignment of the wrist pin ends. 
A bar which is just a nice fit in any one 
wrist pin bushing should pass freely 
through any three of the four on either 
side. 

Before finally putting together the 
two halves of the crankcase, give the 
lapped surfaces a thin coat of shellac, 
being careful to avoid the bearings and 
oil channels, but being sure to cover the 
whole surface. A paper gasket must 
never be used. 



O00S" Loose Ma 



Fit desired^ 



0005' Loose desired^ 
.001 " Max 

.0005" Mm 

.001" Loose desired^ 

.003" Max. 



.00? Mm. 

.0/0" Loose desired — 

.020' Max. 

.0005" Min. 

.0/0" Loose desired'' 

.0005" Min. 

.00/25" Loose desired 

.002" Max. 

000 25" Loose desired- 
0015" Loose Max 

End clearance 
.005 '" Min. 

.008" Loose desired 
.012" Max. 

.0005" Mm. 

001" Loose desired 

.002" Max. 




.008 " Mm 

007" Loose desired 
Oil " Max 



0005' Min. 
.0037" Loose desired 
0072" Max. 

End clearance 
.003" Min. 
010" Loose desired 
012" Max 



■ Key in shaft- side fit 
.0005" tight 
.0005" Loose desired 
.001" loose Max. 
Key in gear - side fit 
.001" Loose desired 
.002" Max. 



0001 Loose Min. 
Tapping fit desired 
001" Loose Max 
Backlash 
006" Loose Mm. 
016" Max. 
0005" Mm. 
.001 "Loose disired 
O02" Max. 

.001" Min 

002" Loose desired 
003 " Max 

.000 " 

OOOS'hght desired 

001 " Ma « 



Fits and clearances for gun synchronizer drive 



WRIGHT AERONAUTICAL ENGINES 



65 



Check Valve must seat 
all around and ho/a 1 Air^ 
Pressure- 



Stroke of P/unqer must 



not be less than }, 



Union must be tight 



.002 Mi'n. 

.007" Loose desired 




000 S " Mm 

001 " Loose desired 

002 " Max. 



Fits for air pump parts of 
all models 



Cylinder Mounting 

Tilt the engine stand to bring one set of pistons ver- 
tical and turn crankshaft till pistons 2 and 3 are at top 
or stroke, as it is easiest to place the block on by taking 
tnese two first. Much the easiest way to compress the 
rings is to make sheet steel clamping rings which can be 
closed with a pair of pliers. There is a special clamp 
used in the factory, which embraces all four pistons at 
once, but to use this properly requires two men to steady 
the clamp and one to lower the block into place so, while 
it gives maximum speed in the factory, it is not worth 
while for field use. 

In replacing the cylinders the oil scraper rings are the 
most likely to slip out of place and are the easiest to 
injure, so they should be watched with particular care. 



Cylinders are sometimes replaced without the cam- 
shafts, but it is better practice to mount the shafts first 
and to have the tappets adjusted to the proper clearance, 
so that nothing remains to be done after mounting the 
cylinders except to time the engine. 

Do not forget that the upper vertical shaft housings 
must be mounted with the cylinder blocks and cannot be 
put on afterwards without removing vertical shaft and 
cam shaft. Mount the magnetos, but not their distribu- 
tor heads, after bolting down the cylinders. 

After timing ( for which operation instructions are 
given on page 67) coat the camshafts with oil and put on 
the covers, using paper gaskets. Start all the holding 
down screws before finally tightening any one of them. 

Carbureter Warning 

A puzzling air leak can sometimes be caused by the 
expansion gland in the intake tee. Therefore, see that 
this is properly packed and tightened. Use new gaskets 
at all points on the intake system and, when putting the 
carburetor in place, observe that neither of the flange 
gaskets on either end is displaced. It is easy to push one 
or other of these a little out of position so that it partially 
blocks the intake. 

Next attach the tachometer drive. To do this slide 
the shaft partly out of the bushing and, bearing on the 
outer end with a screwdriver, put it in place. The shaft 
being slid forward in this way it is possible to see that 
the tongue engages the camshaft properly. Still holding 
the shaft with the screwdriver, push the bushing forward 
and screw it home ; finally, feel the shaft to check that it 
has proper end play. 

Place about a tablespoonful of oil in each cylinder, put 
in spark plugs and, lastly, attach the wiring with the 
magneto distributor heads. 



66 



WRIGHT AERONAUTICAL ENGINES 




r/Af//VG 0/rfL M00£L 




TlO.- 9J£ J/£>£ /*7Q#£L 



TIMING DISC FOR MODELS A I E AND E-2 



The Timing Disc illustrated above is stencilled on one side with the valve setting 
degrees for Models A I E and E-2, and on the reverse side for Models H, H-2 and H-3. 
It is a steel disc with pipe handles which can be unscrewed for packing. The valve 
movements in degrees are shown for all models under items 25 to 30 in the table of 
Specifications at back of book. This is tool WA-13 part number TAM-864. 



TIMING WRIGHT ENGINES 

This Operation is Easy if Done Systematically 
but Difficult if Instructions Are Not Followed 



FOR timing Wright engines it is necessary to be pro- 
vided with a Wright timing disk. This consists of 
a false hub which fits on the crankshaft taper and 
embodies a pair of handles by which the crankshaft can 
be turned and a disk (see page 66) graduated with 
timing marks for all the different models. There is also 
a pointer of sheet steel, having a foot with holes drilled 
in it. so spaced that it fits on the locking wire lugs of the 
two front end blind nuts of the crankcase studs or into 
stud hole on E-2 and H-3. 

The timing disk is attached to its huh by cap screws 
and has slotted holes, the purpose of which will appear 
directly. One side of the disk is graduated with timing 
for Models A, E. I and E-2. and the other side for Models 
H. H-2 and H-3. 

Another essential tool is the dead center indicator, 
since it is essential to find the top dead center very accu- 
rately. 

Procedure 

Put the dead center indicator in number one cylinder 
(propeller end) of the left (left from magneto end) 
block. Mount the timing disk hub on the taper and drive 
it well home so that it is quite tight on the key. Loosen 
the cap screws so that the disk is free in the slotted holes. 
Put the pointer in place. 

Find the approximate top dead center and set the tim- 



ing disk so that it registers top dead center. Then move 
five degrees in one direction and observe the amount the 
dead center indicator has moved over its scale. Return 
to zero and move five degrees the other way, again ob- 
serving the dead center indicator reading. If the indicator 
moves the same amount for five degrees on the timing 
disk either way, then the disk is correct, but if the indi- 
cator moves more one way than another the disk must 
be reset. This operation reads rather complicatedly, but 
is simple enough to perform. 

Model E-2 Valve Setting 

Loosen nut on top of vertical shaft, that is just above 
the upper bevel pinion. Slip down housing of vertical 
shaft as far as it will go and then tan the loosened nut. 
This will separate the serrated coupling and free the 
camshaft from its drive. 

Turn camshaft till the cam of No. 1 left intake valve 
is just contacting with the tappet, having first checked the 
tappet clearance with the special gauge. Note that the 
thick end of the gauge is for use on all the smaller 
engines, the thin end being for Models H, H-2 and H-3 
only. 

Turn crankshaft till pointer registers with opening 
mark for No. 1 left and then tighten up nut drawing ser- 
rated coupling together. Check again before putting in 
cotter pin to make sure that the camshaft has not slipped 




Timing device used on Models E-2 and H-3 engines. Left view shows coupling opened and right view closed in running position. 

Caution — When adjusting the timing device on vertical shaft always slip the housing down so 

you may see that the vertical coupling is in proper mesh 



68 



WRIGHT AERONAUTICAL ENGINES 




Loosening vertical shaft 



Giving vertical shaft half turn 




Changing placing of key in camshaft 



during the tightening. Repeat the whole operation for 
the other block, using cylinder No. 4 right, the disk being 
graduated to suit. 

Timing Older Models 

Owing to the absence of the serrated coupling this is 
a more difficult undertaking. The dead center of No. 1 
left is first found and the disk set just as described above. 
Then, since there is no disconnecting coupling to free the 
camshaft, the next stage is to turn the crank round till 
the disk indicates the opening point for the intake valve 
on No. 1 left. If the camshaft is obviously far out of 
correct position, loosen its bearings, lift it up and set it 
as closely as possible. If set to the nearest tooth of the 
camshaft gear it will probably not be very far out. Now 
tighten down the camshaft bearings and turn the crank 
till the cam contacts with the tappet, having first checked 
the clearance at the back of the cam to the correct end of 
the gauge. The contacting of the cam is easiest tested 
by holding a piece of white paper behind and sighting 
between tappet and cam. 




Changing meshing of camshaft gear 

Now refer to the disk and read off the number of 
crankshaft degrees the shaft is out of time. Note dozvn 
this number and also whether the camshaft is early or late. 

Explanation of Timing Process 

There are 36 teeth in the camshaft gear, so each tooth 
corresponds to 10 degrees of camshaft movement or 20 
degrees on the crankshaft. 

Now there are 15 teeth in the pinion at the top of the 



WRIGHT AERONAUTICAL ENGINES 



69 




Using the tappet adjusting tool and the clearance gauge to 
obtain proper gap between tappet and back of cam 



vertical shaft, so a half turn of the vertical shaft causes 
7y 2 teeth movement of the camshaft, or 75 degrees. 
Therefore, if we lift the camshaft out of mesh, loosen and 
drive up the vertical shaft, turn it 180 degrees and then 
put it back, we have changed the relative setting between 
crankshaft and camshaft by the equivalent of one-half 
tooth ; 5 degrees on the camshaft or 10 degrees on the 
crankshaft. Thus if the camshaft is exactly 10 degrees 
late, as shown on the timing disk, we lift the camshaft 
and vertical shaft, turn the latter half a turn and advance 
the camshaft one tooth, which gives correct setting. 

Next, to get finer adjustment in the camshaft there are 
five keyways and one key, while there is only one keyway 
in the camshaft gear. Five into 36 goes 7 1/5 times, so 
if we remove the camshaft gear, move the key to the 
next keyway and replace the gear, we have moved the 
gear relative to the shaft 7 1/5 teeth. One-fifth tooth 
equals 2 degrees on the camshaft or 4 degrees on the 
crankshaft. So by moving the key one keyway forward 
and then going back in the meshing 7 teeth we have the 
equivalent of a 4-degree advance. 

The finest adjustment is 2 degrees on the crankshaft. 
Since the half turn of the vertical shaft gives ten degrees 
and each keyway 4 degrees, if we go forward three key- 
ways we advance 12 degrees, and we can subtract 10 
degrees from this by making a half turn of the vertical 
shaft ; giving a final result of 2 degrees advance. 

Of course an engine once having been properly set. 



if the gears are not moved on their shafts during over- 
haul, it ought to come to correct time by merely finding 
the right tooth, and the only other thing that could be 
wrong would be the half turn of the vertical shaft. How- 
ever, in timing a motor with new gears, the correct set- 
ting can always be obtained at the first attempt if the table 
on this page is used. 

First find out how much the timing is out, then refer 
to the table, make the adjustment as indicated and the 
timing will be correct within 2 degrees. 

Error, . 

r . , , ,, r . Correction 

Crankshaft Degrees 

2 3 keyways, half turn vertical shaft 

4 1 keyway 

6 4 keyways, half turn vertical shaft 

8 - - 2 keyways 

10 .-. ...Half turn vertical shaft 

12 3 keyways 

14 1 keyway, half turn vertical shaft 

16 .4 keyways 

18 2 keyways, half turn vertical shaft 

20 ..1 tooth camshaft gear 

Of course, the two camshafts have to be timed sepa- 
rately by similar methods. 

Warning 

Cylinder No. 4 right fires next to No. 1 left, so care 
must be taken in setting the timing that this is remem- 
bered. It is easily possible to overlook this and set the 
right block one whole revolution out of time. 

Ignition Timing 

This is also marked on the timing disk. Set the 
crankshaft so that the pointer registers with the ignition 




Operation of timing magneto 



70 



WRIGHT AERONAUTICAL ENGINES 




Wright dead center indicator, which screws in 
spark plug bushing 

point, making sure that No. 1 left or No. 4 right, as the 
case may be, is on the compression and not on the exhaust 
stroke. 

Remove the cotter pin from the magneto coupling and, 
taking hold of the coupling as shown in the cut on this 
page, slide it back till the magneto is free. 

Holding the distributor with the other hand, turn it 
till the high tension brush registers with the proper 
cylinder and till the breaker has just broken. 

Place a cigarette paper between the points and turn 
the magneto back again till the paper is just gripped. 
Then release the coupling and, taking care that the mag- 



neto does not slip, engage the coupling with the gears. 
Do not forget to replace the cotter pin and well spread the 
ends. 

Model A Magneto Setting 

Turn the crankshaft till the parallel surfaces of the 
cams of No. i left cylinder arc on top and set the disc so 
that the piston is 20° and 20' before top center. 

Shellac the bottom surface of the magneto gear hous- 
ing and turn the magneto by hand until the breaker points 
just begin to separate, with the distributor brush in the 
first position to the left of top center. Hold the magneto 
in this position and slip the drive gear through the open- 
ing in the front of the housing. Then permit the mag- 
neto to slide down over the dowel pins and secure it with 
one of the magneto screws. 

Bolt dozen the magneto gear housing with four 6 mm. 
nuts held by lock washers, and put in the remaining three 
magneto bolts. 

Loosen the three bolts and slip the flanged coupling 
until the magneto points are exactly beginning to open. 

Tighten one bolt and test the point of opening by 
turning the crankshaft back and then forward, until a 
piece of tissue paper placed between the points is just 
released, being sure all backlash is held out of the gears 
during the operation. The other magneto is set in the 
same manner and the two must break at as nearly as 
possible the same instant, showing a variation of not over 
half a degree. 



Firing Order 

Model A, I, E. E-2 

(See page 71 ) 



Firing Order 

Model H, H-2. H-3 

(See page 72) 



WRIGHT AERONAUTICAL ENGINES 



71 





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11 



WRIGHT AERONAUTICAL ENGINES 





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CARBURETOR OVERHAUL 

Instructions for Taking Apart Stromberg Carburetor Used 
on Wright Engines and for Inspection and Reassembly 



WHEX overhauling- a carburetor of the twin type, 
that is, with two separate throttle disks, it is never 
wise to remove the disks. In the case of the 
Stromberg- carburetors used on Wright engines it is 
doubly undesirable because the operation of the carburetor 
in idling and acceleration is affected by the precise setting 
of the throttle disks relative to the idling slots in the 
throat. 

Remember that the usual object of overhauling a car- 
buretor is to make sure that all parts are clean, that the 
float valve and seat are in good condition, and that no 
internal parts are loose. Therefore, it is seldom either 
necessarv or advisable to completely disassemble an 
instrument. 

Disassembly 

Before starting to take a carburetor apart read the 
description of its action and adjustment on pages 20 to 27, 
as if this is not fully understood it will be difficult to judge 
the internal condition. 

1. Remove the needle valve plug and the strainer. 

2. Take out the three bolts and two cap screws hold- 
ing the two halves of the body together. 

Remember that the two idling tubes extend through 
both halves, so in separating the parts be careful not to 
bend the tubes. If the halves do not part readily, loosen 
the set screws which lock the venturi in place and tap the 



air entrance lightly with some soft substance. Try not to 
damage the gasket as the operation of the mixture control 
depends upon this being perfectly tight on reassembly. 

3. Remove needle valve seat. In carburetors with a 
serial number after 753156 this is done from the top after 
taking out the needle valve plug. A special screwdriver 
is required as the seat is threaded in very tight. In car- 
buretors with an earlier serial number the seat is screwed 
in from the underside of the body. It is then necessary 
to remove the plug, take out the float fulcrum pin, remove 
the float and then unscrew the seat with a special screw- 
driver. 

Examine the seat for wear, also the needle valve plug. 
Wear is generally confined to the seat, which can be made 
good by grinding if only slightly worn, or may be re- 
placed if badly* pitted. 

Whether the seat is removed from above or below be 
sure to preserve the gaskets under it, as the thickness of 
these determines the level of the fuel in the float chamber. 
In replacing the seat be sure that it is screwed right home. 

There is usually no need to remove the float unless 
this be to get at the valve seat in one of the older car- 
buretors. However, if the float is removed, in replacing 
the float lever fulcrum screw be sure that a 1/32 inch 
hard washer is put beneath the head. If this is left out 
the screw will sink in far enough to bind the float lever. 

After replacing a float make sure that it operates 
freely. 



THROTTLE VALVE 
BODY 



LARGE VENTURI 
TUBE 



SMALL VENTURI 
TUBE 



MAIN DISCHARGE 
NOZ Z L E 



. THROTTLE VALVE 

THROTTLE VALVE SHAFT 

IDLE DISCHARGE JET 



IDLE TUBE 
AIR INTAKE TOJET 
FLOAT 



STRAINER 
NEEDLE VALVE SEAT 




ACCELERATING 

WEL L 

ACCELERATING 
WELL NOZZLE A | R 



GASOLINE CHANNEL 
PLUGS 



HORN CONNECTION 



Section of Stromberg carburetor. See also larger cuts on pages 2 I and 22 



Checking Level 

After removing the float valve seat or the float the fuel 
idle adjustment needle ' eve ^ snou ld be checked, and it is always advisable to check 
t when overhauling a carburetor. To do this take the 
lower half of the carburetor and set it 
up in a vise or on blocks with the top 
surface level, and all plugs, etc., in 
place. Then connect the fuel nozzle 
to a gasoline supply which must be 
under the same pressure as is used in 
the plane. 

Using an ordinary scale measure 
the distance from the top surface of 
the float chamber to the surface of the 
gasoline, which should be If s in. for 
the NA-D4 carburetor and 1 9 16 for 
the NA-D6. A tolerance of 1 32 
either way may be allowed. 

If the level is too high — that is. if 
the scale reads less than l- ; s , the needle 
valve seat must be lowered so that 



GASOLINE 
CONNECTION 

FLOAT LEVER 
FULCRUM SCREW 



FLOAT NEEDLE VALVE 



MAIN BODY 



METERING 
NOZ ZLE 



74 



WRIGHT AERONAUTICAL ENGINES 



the valve will strike it sooner. This means changing the 
gasket under the seat so as to lower it. The amount the 
seat should be moved is one-quarter the error in level. 
Thus if the level is 1*4 below the top instead of the 
desired 1-Vs, then the valve seat needs to be lowered 
1/32 in. 

If the level is too low, this means the valve cuts off too 
soon and the seat requires to be raised. 

Nozzles 

4. Remove the gasoline channel plugs and the accele- 
rating well plug. Then take out the body metering nozzle 
and the idling tubes. It is not usually necessary to remove 
the main discharge nozzles since the gas passages can be 
thoroughly washed out without doing this. 

5. From the upper half of the carburetor remove the 
idle adjusting screws so as to be able to blow out the 
passages. Before unscrewing these, screw them in as 
far as they will go, observing the number of turns for 
each. Note this down. On replacement, run the screws 
right home and then unscrew till the original adjustment 
has been obtained. 

6. In replacing nozzles and plugs be sure they are all 
tight. It is recommended that for carburetor work the 
screwdrivers used should be of the proper sizes and be 



kept in good condition. Burrs on the nozzles can easily 
interfere with the flow of the fuel. 

7. In reassembling the two halves of the carburetor 
see to it that the large venturi are properly seated in the 
lower half and that their lock screws enter the gap in the 
locking ring. 

Check that the surfaces of the halves are undamaged 
and that the gasket is in good condition. Draw the halves 
together with the bolts and cap screws by tightening them 
gradually and in turn. The existence of a perfect joint 
between the halves is essential to the operation. 

Mixture Control 

Do not take apart the pilot's control valve if it is 
working freely, but merely wash it and blow it out with 
compressed air. Referring to the illustration of this part 
of the mechanism on page 23 there is a small hole A 
which should be examined to see if it is clear. Also there 
is a small screen A2 in the entrance to the passage A A 
and this must be clean. 

Note that the NA-D4 and the NA-D6 carburetors are 
identical except that the NA-D6 has no body metering 
nozzle. The half tone cut on page 21 and the line draw- 
ings on page 22 can be compared to show this difference. 
The H-3 has NA-D6A carburetor, which differs slightly 
from the NA-D6 in the number and size of holes in the 
accelerating' well. 



MAGNETO OVERHAUL 

Instructions for Inspection of Magnetos in 
Cases Where Expert Overhaul is not Available 



AS already stated, magnetos should never be handled 
by any but magneto specialists except for cleaning 
''the distributor and adjusting the platinum breaker 
points. None the less a magneto should be taken apart 
for detail examination and cleaning by properly qualified 
men after 100 hours of service. 

The directions which follow describe the taking apart 
and rebuilding of the Splitdorf magnetos used on Wright 
engines, and are intended for the assistance of expert 
magneto hands only. While any first-class mechanic can 
take apart a magneto and rebuild it, to do so is a useless 
procedure unless the man has the special knowledge 
enabling him to judge the condition of the parts. 

Magneto Examination 

Remove the two cotter keys which hold the distributor 
block clasps in position. Press forward the two clasps on 
either side of the block and spring them out, releasing the 
distributor block. Do not remove the wires from the 
distributor block. Remove binding post screw and 
breaker point cover. This is as much disassembly as will 



be necessary for a normal examination of the magneto, 
and, generally speaking, magnetos should not be further 
disassembled. 

Magneto Disassembly 

Loosen the four screws from the sides of the magneto 
near base and remove the two bars and the magneto cover 
plate. 

To remove the magnets place a soft iron keeper against 
the magnet at the base. Remove two nuts and cotter from 
the end of steel strap at driven end of magneto and raise 
strap up. Slip magnet up vertically, then tilt out at bot- 
tom and slide down and out from behind magneto frame 
bolt. Repeat for other magnet. Magnets should never be 
removed without the use of a keeper and should either be 
stored separately with a keeper in place or placed end to 
end with semi-circular cuts on opposite sides. 

Remove screw and disconnect primary winding cable 
where attached to breaker point arm and loosen small clip 
on rotor housing which holds the cable in position. Re- 
move screw and loosen woven copper primary ground 



WRIGHT AERONAUTICAL ENGINES 



75 



connection. Loosen four screws and slip the two clasps 
off the end of the coil core piece. Lift off coil, drawing 
flexible cable out of hole through magneto frame. 

Ibis will be sufficient to give the magneto a careful 
examination and test the strength of the magnets, to clear 
out any dirt which may have accumulated around the 
rotor and to dust the condenser. 

Complete disassembly is accomplished by removing the 
double nuts and lock washers at the top of the magneto 
frame and the two other bolts at the bottom. Remove nut 
ami drive gear from taper end of rotor shaft and pry the 
aluminum castings off of the two dowel pins which hold 
them at their base. Use great care in this operation, as the 
dowels are very tight, being put in place on an arbor press. 
Xext remove the four screws which hold in place the 
rotor housing end plate and bearing support. After 
removing the special screw and the rotor cam, drive the 
rotor shaft back out of the housing (toward driven end). 
This is as far as the magnetos should ever be disassembled 
except when some part of the adjustable breaker frame 
may be actually broken. This frame is adjustable, being- 
held bv three screws which have special grooved heads 
provided with a permanent locking device. The timing of 
the magneto is correctly done at the factory before ship- 
ment and should never be tampered with except for the 
actual replacement of broken parts. In case it is loosened 
it will be necessary to retime the magneto. 

Inspection 

Inspect the rotor member for signs of binding, either 
on the outer face of the soft iron members or on the ends 
of these members. 

Inspect the flexible copper ground connection to see 
that it is clean and tight. 

See that the inner-distributor rotor carbon brush is in 
good condition and makes good contact with the high 
tension winding. Examine the platinum points to see 
they are free from serious pits, have a smooth contact 
surface and are adjusted to 0.018 to 0.022 clearance when 
wide open. 

Reassembly 

Reassemble rotor shaft and ball bearings in rotor 
housing, using extreme care that all parts are entirely 
clean and that the ball bearings are packed in with a small 
amount of vaseline. Great care must be exercised that 
the two spacing washers on the rotating shaft are of such 
thickness that the shaft has 0.002 to 0.004 play, both 



■\, 




Magneto opened up for inspection. Cut is 
diagrammatic only. 

between the collars on the shaft and between each collar 
and the opposite front or back plate. Also that the 
rotated member is in the center of the field structure so 
that a 0.003 feeler gauge can be passed completely around 
it in any position. If this rotor should bind at any point 
heat will be produced and it may eventually break the 
shaft. 

Replace the drive coupling part and the cam with its 
lock screw. Also replace the magneto drive coupling part 
together with its nut and cotter pin at the driven end of 
the shaft. 

Reassemble the coil, being sure that the winding clamp 
screws are tight and that their lock nuts are tight. Also 
that the wire connections are clean and tight. 

Replace the magnets, being careful that the magneto 
support pieces are in place. Screw the magneto strap 
down tight and lock it by tightening the double nuts 
against lock washers. Replace magneto cover. Replace 
breaker cover and terminal screw. Thoroughly clean the 
inside of the distributor box of all free carbon and replace. 



76 



WRIGHT AERONAUTICAL ENGINES 



Table of Specifications Covering Wright Aviation Engines 

GENERAL A I E E-2 H H-2 H-3 

1. Number of cylinders 8 8 8 8 8 8 8 

, D 120 mm. 120 mm. 120 mm. 120 mm. 140 mm. 140 mm. 140 mm. 

"■ Bore " 4.724 in. 4.724" 4.724" 4.724" 5.51" 5.51" 5.51" 

, Cf 1 130 mm. 130 mm. 130 mm. 130 mm. 150 mm. 150 mm. 150 mm. 

■>■ Mroke 5.118 in. 5.118" 5.118" 5.118" 5.9" 5.9" 5 9" 

4. Piston displacement »A 7 « £ "/« «■ #]?««■ }} k 762 «■ Iff * cc. l|f 5 cc. 18 475 cc. 

/18cu. in. 718 cu. in. 718 cu. in. 718cu.in. 1127 cu. in. 1127 cu. in. 1127 cu: in. 

5. Compression ratio 4.72 4.72 5.33 5.5 5.4 5.5 5.5 

6. Guaranteed brake horse-power sea level 150 H.P. 150 H. P. 180 H.P. 190 H.P. 320 H. P. 320 H P 320 H.P 

29.27" at normal R. P. M 1450 R.P.M. 1450 R.P.M.1800 R.P.M.1800 R.P.M.1800 R.P.M.1800 R.P.M.1800 R.P.M. 

7. Direction of rotation of crankshaft (look- 

ing at magneto end of engine) Clockwise for all models 

8. Direction of rotation of camshafts (look- 

ing at magneto end of engine) Anti-clockwise for all models 

9. Tachometer shaft speed Half crankshaft speed for all models 

10. Direction of rotation tachometer shaft 

(looking at magneto end of engine) Anti-clockwise for all models 

11. Weight of engine complete with propeller 

hub flange and bolts, carburetor and two 
magnetos. Without water, oil, radia- 
tors, tanks, starting device, gasoline, 

supply system or propeller 432 472 472 480 625 617 620 

12. Weight as in 11, but with cyl. jackets full 

of water. Water in radiator, etc., not 

included 473 513 513 520 680 672 672 

13. Position of center of gravity of engine 

under conditions (11) : 

Back from hub rear flange 19 13/32" 2117/32" 2117/32" 2111/16" 23 13/32" 23 13/32" 23 13/32" 

Up from center line of crank shaft 5" 5" 5" 5 11/32" 6A" Wa" 6 l A" 

14. Width requisite between engine bearers 11^4 11^ ll/ 2 U% 13^ 13^ 13Mi 

15. Width between engine holding bolt centers.. 13 5/32 13 5/32 13 5/32 13 5/32 14 5/16 14 5/16 14 5/16 

16. Number of holding down bolts 16 16 16 16 16 16 16 

17. Size of holding down bolts Vs, 3 A Y& Y% V& Vs % 

Overall length from end to end of mag- 
neto 51K 50 23/32 50 23/32 49^ 5115/32 52 9/32 52 9/32 

Overall width outside of cam covers 33 7/16 33 7/16 33 7/16 33 7/16 38^ 38?^ 38^ 

Height from engine bearer to highest point- 
top of pet cocks 18^ W/ 4 18% 18J4 23^ 23^ 23^ 

IGNITION 

18. Magneto type Dixie 800 Dixie 800 Dixie 800 Dixie 800 Dixie 800 Dixie 800 Dixie 800 

19. Direction of rotation of magneto Anti-clock Anti-clock Anti-clock Clock Anti-clock Clock Clock 

R. h. (looking at drive coupling end) 1. h.... Anti-clock Clock Clock Clock Clock Clock Clock 

20. Magneto speed Crankshaft Crankshaft Crankshaft Crankshaft Crankshaft Crankshaft Crankshaft 

21. Magneto breaker point gap 0.02" 0.02" 0.02" 0.02" 0.02" 0.02" .02" 

21. Spark plug point gap 0.02" 0.02" 0.02" 0.02" 0.02" 0.02" .02" 

-,-, ^, ., u i r a *„„„„* 2 mm. 2 mm. 2 mm. 2 mm. 0.03" 0.03" .03" 

23. Clearance between back of cam and tappet.. Q-,g„ g-,g„ ^L„„ () _g„ 

24. Advanced spark occurs crankshaft degrees 

before top stroke 20° 20° 25° 25° 25° 25° 25° 

VALVES AND TIMING 

25. Intake closes 50° late 50° late 50° late 50° late 60° late 60° late 60° late 

Intake opens 10° late 10° late 10° late 10° late 10° early 10° early 10° early 

26. Exhaust opens 45° early 45° early 45° early 45° early 61° early 61° early 61° early 

Exhaust closes 10° late 10° late 10° late 10° late 26° late 26° late 26° late 

17. Intake remains open (crankshaft deg.) 220° 220° 220° 220° 250° 250° 250° 

28. Exhaust remains open (crankshaft deg.)..- 235° 235° 235° 235° 267° 267° 267° 

29. Strength of outer valve springs, when com- 45 45 45 45 45 45 45 

pressed to length of 1 9/16 1 9/16 1 9/16 1 9/16 1 9/16 1 9/16 1 9/16 

30. Strength of inner valve springs, when com- 35 35 35 35 35 35 35 

pressed to length of 1 7/16 1 7/16 1 7/16 1 7/16 1 7/16 1 7/16 1 7/16 

For valve adjustment see page 49 49 49 49 49 49 49 

Overhaul see page 55 55 55 55 55 55 55 

7 < n . Zenith Stromberg Stromberg Stromberg Stromberg Stromberg Stromberg' 

31. Carburetor type 48 D.C. N.A.D. 4 N.A.D. 4 N.A.D. 4 N.A.D. 6 N.A.D. 6 N.A.D. 6A 

32. Average fuel consumption per H. P. hour 

at normal R. P. M 0.55 lb. 0.55 lb. .50 .48 .52 .48 .48 

33. Approximate consumption at sea level gal- 

lons per hour at normal R. P. M. and 

guaranteed H. P., 6.25 lbs. gas per gal 13.2 gal. 13.2 gal. 14.3 gal. 14.5 gal. 26.6 gal. 24.6 gal. 24.6 gal. 

34. Correct pressure on fuel supply 2.5 lb. 2.5 lb. 2.5 lb. 2.5 lb. 2.5 lb. 2.5 lb. 2.5 lb. 

35. Diameter of venturi throat : 30mm. V/ 2 " \y 2 " V/," 113/16" 113/16" 113/16" 

For carburetor adjustment see page 24 24 24 24 24 24 24 

For carburetor overhaul see page 71 71 71 71 71 71 71 



WRIGHT AERONAUTICAL ENGINES 11 

A I E E-2 H H-2 H-3 

LUBRICATION SYSTEM 8 8 8 8 8 8 8 

36. Average oil consumption per H. P. hour 022 lb. .022 lb. .018 .018 .022 .018 .018 

37. Approximate consumption on ground gal- 

lons per hour 45 gal. .45 gal. .44 gal. .45 gal. .96 gal. .80 gal. .80 gal. 

At normal R. P. M 1450 1450 1800 1800 1800 1800 1800 

38. Correct oil pressure at normal R. P. M 501b. 501b. 701b. 701b. 701b. 701b. 701b. 

At recommended oil temperature 150° F. 150° F 150° F 150° F 150° F 150° F. 150° F. 

39. Quantity oil circulated per min. under con- 

ditions of (38) 2.2 gal. 2.2 gal. 2.2 gal. 1.25 gal. 1.25 gal. 1.25 gal. 1.25 gal. 

40. Minimum safe quantity of oil in whole sys- 

tem IK' gal. 2 gal. 2 gal. 2 gal. 3 gal. 3 gal. 3 gal. 

41. Maximum permissible temperature of oil 90° C 90° C 90° C 90° C 90° C 90° C 

under worst conditions 200° F 200° F 200° F 200° F 200° F 200° F 

42. Desired maximum oil temperature in nor- 

mal operation 160° F 160° F 160° F 160° F 160° F 160° F 

43. Speed of oil pump 1.2 x crank 1.2xcrank 1.2xcrank Crank Crank Crank Crank 

44. Direction of rotation of oil pump (looking 

at driving end of shaft) Anti-clock Anti-clock Anti-clock Clock Clock Clock Clock 

45. Hose connection required between engine 

and piping: 

Inside diameter 13/16" y 4 "— A" Va"— 1 A" 3 A"— l A" 3 A"— l A" 3 A" 3 A" 

Number of pieces 2 4—1 4—1 2—1 2—1 2 2 

WATER SYSTEM 

46. Free delivery water pump in gallons at nor- 

mal R. P. M. of engine 25 25 40 25 56 56 56 

47. Speed of pump 1.2 crank 1.2crank 1.2crank 1.2crank 1.2crank 1.2crank 1.2crank 

48. Direction of rotation of pump looking at 

driving end of spindle Anti-clock Anti-clock Anti-clock Anti-clock Anti-clock Anti-clock Anti-clock 

49. Desirable water temperature at cylinder 

outlets 110° F 110° F 110° F 110° F 110° F 110° F 110° F 

50. Maximum permissible water temperature 80° C 88° C 88° C 88° C 88° C 88° C 88° C 

at cylinder outlets 190° F 190° F 190° F 190° F 190° F 190° F 190° F 

51. Hose connections required between engine 

and piping: 

Inside diameter 1 3/16" 1 3/16" 1 3/16" 1 3/16" 1 3/16" s/ s " 13/16" 

Number of pieces 4 4 4 2 6 5 7 

Inside diamater \y 2 li 9 5 ItV 1-fV" 

Number of pieces 1111 

Inside diameter 1,V 

Number of pieces 6 

PISTONS 

52. Permissible weight variation between piston 

assemblies in each set of four 1% 1% \% 1% 1% 1% 1% 

53. Number of compression rings per piston 4 4 4 4 4 4 4 

54. Number of compression ring grooves per 

piston 2 2 2 2 4 4 4 

55. Number of right hand rings required for 

one piston 2 2 2 2 

56. Number of left hand rings required for 

one piston 2 2 2 2 

57. Number of oil scraper rings required for 

one piston 1111111 



78 



WRIGHT AERONAUTICAL ENGINES 



WRIGHT ENGINE TOOL LIST 



WRIGHT ENGINE TOOL LIST 

LIST A 
Tools common to all Models 

Service A r o. Name Tool No. 

WA1 Camshaft Line Reamer TA-11108-D-92 

WA2 Camshaft Bearing Aligning Bar......TAM-865 

WA 3 Cylinder Holding Stand (supplied 

.in blueprint only) TAM-866 

WA4 Dead Center Indicator 12192-T-10 

WA 5 Engine Stand, tilting (supplied in 

blueprint only) TAM-863 

WA 6 Gear and Ball Bearing Puller 121S9-T-S 

WA7 Handle for Valve Seat Cutters TAM-860 

WA 8 High Speed Wrench Handle No. 6 
and Sockets Nos. 16 to 28 inclu- 
sive Billmont Wrenches 

WA 9 Lock Nut Socket Wrench ( Crank- 
shaft) TA-12159-T-15 

WA10 Magneto Driveshaft Gear Puller....ll905-T-12 

WA11 Propeller Hub Wrench Assy 12300 

WA 12 Spark Plug Bushing Wrench Assy...l2066-E-7 

WA 13 Timing Disk Assy TAM-864 

WA 14 Valve Assembling Frame (supp'ied 

in blueprint only) TAM-862 

WA 15 Valve Assembling Lever TA-12066-E-6 

WA 16 Valve Clearance Gauge TAM-85S 

WA17 Valve Grinding Screwdriver TA-12066-E-27 

WA 18 Valve Guide Socket Wrench Commercial 1" long 

socket 

WA 19 Valve Tappet Socket Wrench TA-12066-E-18 

WA20 Valve Tappet Adjusting Wrench-14072 

WA21 Water Pump Bracket Nut Wrench TA-12066-T-82 

WA 22 Water Pump Gland Wrench 14049 

WA 23 Adjustable Hook Spanner Wrench.. 14050 
WA 24 Adjustable Hook Spanner Wrench..l4(>51 
WA25 Spark Plug Wrench and Handle. .:.14()52-14053 

WA26 Cylinder Stud Nut Wrench Can use either 12066- 

T-72 or 14054 for 
all engines 



LIST B 
Additional Tools required for Models E and I 

WA51 Crankshaft Thrust Bearing Nut 

Wrench TA-12066-T-65 

WA 53 Main Bearing Reamer L..TA-12045-C-2 

WA54 Piston Pin Bushing Reamer 10537-T-51 

WA55 Valve Guide Plug Gauge Exhaust..TA-11279-A-l 

WA 56 Valve Guide Plug Gauge Intake TA-10484-A-26 

WA57 Valve Guide Reamer 12075-C-8 

WA58 Valve Seat Cutter and Pilot Ex- 
haust TAM-857 

WA 59 Valve Seat Cutter and Pilot In- 
take ■ TAM-856 

Note — The handle for these cutters has formerly 
been duplicated and supplied with cutters TA-12066- 
T-89 and 90. The pin attaching handle to cutters should 
be changed so that the handle can be supplied with the 
tools common to all motors and the cutters interchanged 
on the one handle. 



LIST C 

Service No. A r amc Tool No. 

Model A requires all the Tools in Lists A and B with the 

exception of Nos. 10 and 11. 

It also needs the following : 

WA 71 Piston Pin Lock Screw Wrench 12015-C-2 

WA 72 Propeller Hub Nut Wrench TA-12066-T-94 

LIST D 
Models H, H-2 and H-3 require all Tools in List A. 
Plus the following: 
WA 91 Crankshaft Thrust Bearing Nut 

Wrench 12159-T-17 

WA 93 Main Bearing Reamer 13263-T-37 

WA94 Piston Pin Bushing Reamer 11493-T-6 

WA95 Valve Guide Plug Gauge Exhaust..ll485-T-2 
WA96 Valve Guide Plug Gauge Intake....ll568-T-13 

WA97 Valve Guide Reamer 12128-T-12 

WA98 Valve Seat Cutter and Pilot Ex- 
haust TAM-858 

WA99 Valve Seat Cutter and Pilot In- 
take TAM-859 

Note — These cutters are portions of 12104-T-l and 
12104-T-5. They should be supplied without the handle 
as they will fit Handle No. 7 in List A after pin is rede- 
signed. Refer to note on valve seat cutters for Models A, 
E and I at foot of List B. 

Tool Box. The following tools are supplied in Tool Box of 
each engine as it leaves the Wright Plant : 
WA 11, 20, 22, 23, 24, 25. 

If only one engine is being used, the following single engine 
tools will be sufficient to make most of the adjustment necessary 
in addition to the tools supplied in Tool Box : 

Single engine tool list for Models I, E and E-2 — 

WA 3, 4, 5, 7, 8, 12, 13, 14, 15, 16, 17, 18, 19, 21, 26, 51, 58, 59. 

Single engine tool list for Model A — 
WA 3, 4, 5, 7, 8, 12, 13, 14, 15, 16, 17, 18, 19, 21, 26, 51, 58, 59, 
71, 72. 

Single engine tool list for Models H, H-2 and H-3 — 
WA 3, 4, 5, 7, 8, 12, 13, 14, 15, 16, 17, 18, 19, 21, 26, 91, 98, 99. 

If several engines are at a station, a fuller complement of 
tools should be kept and the following list is suggested in addition 
to the tools supplied in Tool Box : 

Several engine tool list for Models I, E and E-2 — 
WA 3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 17, 18, 19, 21, 26, 51, 
54 55, 56, 57, 58, 59. 

Several engine tool list for Model A — 
WA 3, 4, 5, 7, 8, 9, 12, 13, 14, 15, 16, 17, 18, 19, 21, 26, 51, 54, 55, 
56, 57, 58, 59, 71, 72. 

Several engine tool list for Models H, H-2 and H-3 — 
WA 3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 17, 18, 19, 21, 26. 91, 
94, 95, 96, 97, 98, 99. 

For a base where many engines are to be overhauled and 
repaired, the entire list of tools should be obtained for the models 
of engines coming into the base. This would supply the base with 
some of the large tools such as reamers, aligning bars, etc., which 
would be seldom used if only a few engines are being served. 



